Prismatic corrections – a communication challenge between the industry and opticians

Prismatic corrections – a communication challenge between the industry and opticians

Picture by Michael Dziedzic on Unsplash

In my career of over 30 years as a lecturer in ophthalmic optics, I have been through all the stages from student to teacher to developer to expert authority – trusted with confidential knowledge about the industry. I would like to thank everyone for the trust they have shown in me, because this was the only way I was able to explain complex optical issues to opticians in a clear and understandable way. Here aberrometry with its wavefront measurement is a case in point.

By Fritz Paßmann

Knowledge means recognizing connections and developing links to topics that are already understood. The conversion of prismatic prescriptions into spectacle lenses that a wearer is comfortable with is something I care deeply about. Both from the point of view of the end customer, i.e. the improvement of his vision and possible alleviation of asthenopic complaints, as well as from the point of view of the optician, who needs support in exercising his skills and offering his – sometimes emotional – recommendations. This calls for broad backing by the industry. This article is aimed at bringing about a willingness to offer opticians more information, education and transparency.

This is a huge challenge: converting values ​​determined in the refraction room into spectacle lenses that are comfortable for the end user. It requires close cooperation between all the parties involved. The optician is the link between the lens manufacturer and the customer.

Let’s start at the beginning

When looking through a spectacle lens, a prismatic effect is created outside the optical center. Normally this does not pose a problem for the spectacle wearer, as the prismatic effects of different versions and base settings mutually diminish each other resulting in an “almost zero” overall prism; except where there is anisometropia, in particular in the principal meridian of the spectacle lens in the respective direction of view.

To calculate this, the optician uses the “Prentice law”: P = c * S`. Charles F. Prentice is considered as the father of optometry in the USA and in 1921 he recognized the connection between the distance of the path of the light beam in the spectacle lens from the optical center to the vertex power for calculating a prismatic effect.

If someone wants to achieve a prismatic effect by decentering the lens, they must not use the Prentice law as the formula does not take account of the rotational direction of the eye when looking through the lens. For more accuracy, the ‘Weinhold formula’ or ‘extended Prentice law’ (Fig. 1) which includes the BVD (back vertex distance) must be used.

‘extended Prentice law’

Technically the distance between the eye center of rotation and the lens vertex b` should be taken into account, as the eye rotates around its optical ocular center Z` in the opposite direction to the base setting of the prism. But how can you measure the distance to a virtual point? This raises three fundamental questions for the lens manufacturer:

  1. Is the BVD or b´ always included when ordering prismatic lenses? In which case a specifically developed order form including all the necessary data is recommended.
  2. What distance does the industry use to calculate b’? The ‘standard eye’ according to Gullstrand specifies 13.5
  3. Is there any conversion made between ‘Prentice’ and ‘Weinhold’?

This leads to a further issue: the difference between the measurement position and the position of use of the spectacle lens which needs to be communicated precisely, both for the clarity and understanding of the optician and for the technical details to be printed on the lens bag. Admittedly the differences in calculation will mostly have an effect ‘after the decimal point’, i.e. in the decimal range.

However in problem cases several factors often occur together, or the customer is particularly sensitive, in which case precise communication can minimize misunderstandings.

Prismatic effect through decentration and its limits

The application of the Prentice law is already taught during training and thus opticians are able to autonomously decenter the lenses and determine the reference point in order to achieve the desired prismatic effect. I was already proud to be able to do this in the early days during my apprenticeship. At a time when considerable subsidies were still paid by the health insurance for spectacle lenses (editor´s note: that was the case in Germany until 2004), ordering a spherical or toric single vision lens (multifocal lenses naturally did not apply) and achieving a prismatic effect with the help of a larger uncut lens diameter was a great art and did not involve changing the prescription or even cheating the health insurance.

The desired effect was achieved and afterwards it was not possible to see by the lens how this had been done. However, this approach does have its limits, which should be clearly communicated by the industry:

  1. The vertex power and uncut lens diameter are mutually dependent. That means that, where S` is rather low, the blank will not have the required diameter. My recommendation for maximum dioptric power is the number “4”. This means that above a vertex power of0 D and prismatic effect of 4 cm/m, the prism should be created industrially, i.e. by tilting the blank when blocking. This procedure is not known to all opticians, but it explains the limitations of what is feasible when the blank only has a limited edge thickness.
  2. For toric lenses the effect in the meridian must be taken into account. This means that where the principal meridian and the base setting of the prism to be generated are not parallel to each other but intersect obliquely, this approach tends to lead to approximate results.
  3. If the lens manufacturer is not aware of the prismatic effect to be achieved, the increased aberrations that inevitably occur will not be corrected or even minimized. At this point the occurrence of ‘astigmatism of oblique bundles’ in wedge-shaped lenses should just be mentioned. An optimized prismatic correction for the comfortable vision of the spectacle-lens wearer requires the aberrations to be corrected at the reference point.

Mandatory: BVD and PD

During training to become a refractionist (not a refraction assistant), a distinction is made in the correction of a latent squint (heterophoria & associated heterophoria – explaining the difference would require a chapter of its own) between the pupil-center centration (PMZ) and the formula-case [1] when using a trial frame [2]. When centering on the pupil center using the Viktorin method, the PD setting is retained during the entire measurement process.

On the one hand, this is a straightforward procedure, on the other hand, it contains inherent inaccuracies and may even reach its limits. As already mentioned, after inserting a prism the customer no longer looks through the optical center of the existing sphero-cylindrical correction. Two prismatic effects occur: that of the measuring prism and the unwanted prismatic power of the spherical and toric lenses, leading to a weakening or strengthening of the overall prismatic effect.


The refractionist does not know the overall prism value and has to rely on the expertise of the lens manufacturer to produce the exact prismatic effect. However, to do this, as already mentioned, the PD and BVD need to be known. A prismatic prescription cannot be followed precisely without specifying the PD and BVD.

Furthermore, the visual acuity/vision of the customer may be impaired during refraction due to the resulting aberrations, which may lead to the refractionist giving up on further prismatic correction, although the status of binocular vision of the customer could still be improved. In addition, the binocular field of vision becomes smaller.

When using the equation case for lens centering, the far distance centration (not the customer´s PD) is adjusted. Two similar rules of thumb are used which are by no means only marginally different: for every 3cm/m or every 4cm/m, the set distance in the trial frame is corrected in the opposite direction to the base setting of the inserted prism. This minimizes the prismatic effect of the main lens but by no means removes it completely.

Furthermore, new questions arise as to the practical procedure used: if the formula is only used from 3 cm/m or 4 cm/m, what procedure is to be followed below these values? In the case of higher vertex powers, a noticeable prismatic side effect quickly becomes apparent, even if the trial lenses used are of low prism. What is the right setting for 5 cm/m on the trial frame? The required accuracy of 1.67 mm or 1.25 mm cannot be achieved.

In practice, this results in a combination of the two variants: partly further adjustment, partly accepting the prismatic side effects of the main lens. I recommend making the size of the ‘readjustment’ dependent on b`. The larger the VD, the more likely is it necessary to make readjustments. This results in the next demand on the measurement protocol/order form for spectacle lenses with prismatic effect: the indication of the PD at the beginning and at the end of measurement as well as the BVD. As previously stated, progressive lenses must always be ordered with the prismatic effect.

Potential sources of communication errors between the optician and the lens manufacturer

The question sometimes arises for the optician: “If the customer’s PD is readjusted already during refraction, (I am deliberately using this imprecise wording here because it is so often used; which does not make it any more correct. The correct terminology would be to readjust the centration point distance in the trial frame) then do I no longer have to take it into account when readjusting?” The answer is: “It depends.”

The crux of the matter is that it depends on the optician’s workflow. A refraction is usually carried out after taking down the case history and assessing the requirements. The PD setting of the trial frame is rarely recorded. The optician takes the centering data from his centering system using the – hopefully correctly adjusted – trial frame.

However, at this point the prismatic correction is not in front of the eyes, so they take the ortho position. This data is then sent to the lens manufacturer. In this case, the centration correction must be carried out over the entire prismatic effect, not just over the ordered prism, regardless of whether readjustment has already occurred in the refraction room.
If the optician specifies the readjusted PD when ordering the lens, only the small difference to the newly calculated total prism needs to be changed. In my opinion, it is desirable to indicate this correction on the lens bags as the new “distance centration distance”.

Some lens manufacturers have recognized this potential source of error in communication and have for some time now been taking a new approach, at least for progressive lenses: relocating the stamp by moving the engraving. The lens manufacturer calculates the new position of the reference point exactly, i.e. to an accuracy of 1/10 mm, thereby offsetting the centration marking of the stamp which makes sense. The optician has one less thing to worry about and continues to work as usual. However this is not a general solution to the problem.

New questions arise: “Can this approach be used for all types of lenses in the portfolio?” Is the centration correction clearly shown in the price list? At what point in time was the change made?” This question may be of key significance when handling complaints. Since specialist opticians usually work with a number of lens suppliers: “Which lens manufacturers offer this, and which do not?”

Prism distribution

Personally, I prefer asymmetrical prism distribution. I find it satisfying when aesthetically pleasing lenses can be achieved by adjusting the thickness. It is down to the refractionist to decide whether a symmetrical or asymmetrical distribution of the prismatic effect is more appropriate. Only he knows the visual acuity and the tolerance of any prism combinations as well as the influence of the customer’s “dominant eye”.

Only the lens manufacturer can calculate the absolute effective thickness ratios for ground lenses with a sphero-cylindrical and/or progressive surface. From these two points of view, an interaction is recommended through which all possibilities can be envisaged.

Taking account of the refraction conditions in the trial frame

The lens manufacturer should have a further skill and needs to communicate this to the optician: namely modification of the overall prism in the finished lens. In the refraction trial frame, lenses are placed in different holders, whereby the prismatic trial lens with its base setting is usually inserted into the front lens holder for practical reasons. The lens is thicker and would otherwise scratch the subsequent lenses or would not even fit into the lens holder. However, in the end only one lens is manufactured and ground to fit into the customer’s spectacle frame, with the resulting effect corresponding to the sum of all the individual lenses.

This poses additional questions: Are the various distances between the trial lenses taken into account when calculating the spectacle lens? Is the forward prism wedge of the trial lens converted into the same effect on the spectacle lens in which the prism wedge protrudes backwards? How is the prismatic trial lens labeled? According to DIN, the basic deflection of the prism is defined in such a way that the principal beam hits the front surface at a right angle and deflection only takes place at the rear surface. Has the trial lens already been adjusted in this regard and, with the wedge protruding forward, does it have the same effect as is required in the position of use of the corrective lens for the main direction of view, despite the principal beam being refracted twice?

Measurement position versus position of use

In addition, there is the well-known problem of distinguishing between the measuring position and the position of use. The requirement for the measurement protocol/order form for spectacle lenses with prismatic effects should therefore include information on the respective slots used. In this context, the position of the edge of the ground-in spectacle lens is also important. Usually, only the optician has exact knowledge of the spectacle frame in question. Only the details of the lens shape are passed on to the lens manufacturer.

However, if the details of the entire frame – with its material, type of manufacture and the possibility of hiding the thickness of the lens rim – are passed on, new possibilities of producing aesthetically pleasing spectacle lenses by shifting the facet are opened up.

In addition, the position of the spectacles on the face is important. Are there any anatomical features such as strong eyebrows or deep-set eyes or protruding cheekbones to be considered? If you want the standard facet to deviate from parallel to the front surface, i.e. to be incorporated in the middle or even in the rear third of the edge thickness, this option must also be made clear on the order form.

Interplay between lens thickness, transparency and color fringe

I would also like to see more information about different lens materials and their Abbe number. This knowledge should then be used to advantage by the optician during the consultation. Thinner and more expensive does not always mean lighter and better!

Using easily understandable graphic charts, the interplay of lens thickness, transparency and color fringe of spectacle lenses can be used as a sales-support material to find the ideal combination, thus leading to the greatest benefit for the customer.

Taking account of the reference point

In the next point, too, I would like to plead for a commitment to sustained communication by the industry to the optician: “How can I (the optician) check lenses for prismatic effect?” This is only possible at the reference point. For this reason, single vision lenses should always be delivered with the reference point marked on them.

In the case of progressive lenses, the corrective prism effect cannot be measured solely at the prism reference point. At this point, the prescription prism and the calculated thickness reduction prism of the lens manufacturer have to be considered together. Often the optician is not aware of this combined effect. In addition with a height prism, the difference between the prismatic effects must be calculated separately from right to left.

One question after another

With regard to the previous point, the optician needs the expertise of physicists and physiologists from the industry. What does the spectacle wearer need to know about prismatic corrections? What tips and recommendations can the optician pass on to his customer? The comment “You’ll just have to get used to it!” is simply not good enough and certainly not professional.

How do increased distortions and dispersions affect vision? What can help to reduce these aberrations? How can it be that a customer reports seeing colored objects in different layers due to color stereopsis? Can anything be done about this? Can micropsia (objects appearing to be smaller) and macropsia (objects appearing to be larger than they are) be identified and avoided during eye testing for spectacle lenses?

Questions upon questions that can only be satisfactorily answered through a cooperative partnership where both sides bring in their expertise.

In conclusion, I hope that this article will create a better understanding of the vital need to collect all this data. A certain amount of transparency is desirable for calculating ideal lenses in order to demonstrate both the quality of the lenses and to stand out from the competition. This applies equally to lens manufacturers and opticians.

[1] Formula case means that the pupil distance in the trial frame is corrected by 1 mm against the base for every 4 cm/m. An example: Initial situation; PD 32 mm, 4cm/m base-in, then the trial glasses are readjusted to 33 mm.
[2] A Trial Frame is an adjustable spectacle-like device containing cells used to hold multiple trial lenses during subjective refraction.




And the winner is …

And the winner is …

Picture by Peter Fischer auf Pixabay

How market data in optics comes to life: When Mark and Ingeborg Mackenzie began to conduct studies on the global optical industry in 2003, Ferrari won the Formula 1 with Michael Schumacher. At that time, the industry experts described Asia as the “Ferrari” of ophthalmic optics – and thus the undisputed number one on the world market.
In 2021, Ferrari is no longer a synonym for Formula 1 world champions, and the optical world market has also changed. But which three candidates are on the optical winners’ podium today? And which country has the greatest future potential? By Hanna Diewald

In this interview Mark Mackenzie explains how to create reliable market data, how and why COVID-19 has affected the global market in extremely different ways and how several countries have developed over the past 16 years. Some of Marks predictions from the year 2004 were absolutely right, whereas other forecasts turned out to be wrong. That does not surprise, as none of the most experienced experts could have predicted some of the global political events, which disrupted the world in the last years and therefore also affected the eyewear industry.


Mark Mackenzie

You have been researching the global optical market for 20 years. How did that happen?

I went into the optical industry in 1994. In 1999 I joined Carl Zeiss and I realized how difficult it was to find good research on the optical market. You could get research for one country that was good, but in another country, it was done in another way. I felt if one could conduct research across the optical industry with people who understand optics and using the same methods in every country, that this would be a service which could be of interest to other companies in this sector as well. So, we started Strategy with Vision in 2001. In the last four years alone we have done 78 studies.


What are the objectives of the “world lens and frame demand study 2020”?

The objective was to estimate the total number of optical outlets operating in 2019 in the countries researched. To assess the number of ophthalmic lenses sold worldwide and to make an estimation of the number of ophthalmic frames sold by country. We wanted to assess the ophthalmic lens and frame market in value at net manufacturers/wholesalers selling prices to optical retailers in local currency. And finally, we wanted to make a growth forecast for ophthalmic lenses and ophthalmic frames in volume and net value by country for the period 2019 -2022.


How many countries were researched?

For the study – I talk about today – we collected data from 63 countries. We did the work in 2020, the year measured was 2019. These 63 countries are presenting 94% of the gross domestic product and they make up 78% of the total population in the world.



You compared your first study from 2003 with the current outcomes. What are the most interesting trends?

We said in 2003 that Asia was the undisputed Ferrari of the ophthalmic world because at that time Ferrari was the car winning the Formula 1. We stated also that Western Europe lies in third position in the world league table but not even the increase in the European Union to 25 members would allow them to catch up with North America. On the positive side the new European Union with a total population of 455.5 million inhabitants at that time, of which 187.5 million were over the age of 45, would provide a potential for much higher demand in the future. And we advised lens companies to look more carefully at the markets of the Near East.

Then we looked at the data today – 16 years later. We got the forecast of Asia growing fast correct. It is the market which has grown the most from 2003 to 2019. It grew by 3% per year from 326 to 536 million lenses. Western Europe has actually overtaken North America, although the population isn´ t growing very fast in Western Europe – but they have been very clever. They sold second pairs successfully across several countries and could therefore overtake North America. But we got the European Union totally wrong because we did not forecast Brexit and so the European Union has actually shrunk since 2004 from 455 to 447 million people. However, the number of people over the age of 45 is growing to 210 million and the markets of the Near East and Middle East have grown by 3.6% per year. That didn´t surprise us because we had told people that they should look at it. In those days, Syria and Yemen were countries that were showing economic growth. Now Syria is in civil war, but countries like Turkey and Iran have shown an enormous amount of growth.


Which further outcomes are important?

The ophthalmic lens market in volume grew from 2003 to 2019 on average by 2.6% per year. That has been a rate of growth which has been very constant. It is not surprising because this industry relies on population growth and the GDP because you need money to buy those glasses. These factors all together lead to long-term growth. The population grew by 1% per year, the GDP by 2% a year. But I said has proved very regular because this clock mechanism, which was perfectly working until 2019, has now stopped working regularly across the world, due to coronavirus. What may surprise people: single vision has remained at the same unit share in the last sixteen years, from 76% in 2003 to 75% in 2019.

We always talk about progressive growth but one of the big reasons for the increase in progressives was the decline in bifocals. What is perhaps surprising is that progressives now make up 60% of total lens value but ten countries in the world make up 70% of the total world value of progressive lenses. This shows how dependent we – I mean the whole optical industry – are on just these ten countries in the world: USA, France, Germany, Japan, Brazil, UK, Canada, Italy, Spain, and India.


Can you guess the reasons?

They tend to be countries with quite an old population, they are all countries with high income per capita, and they are partly countries which have social medical health plans which include eyewear.


                                                                                                                        Which products have the biggest potential in the future?

I think progressives will continue to grow. Even if we are affected economically by COVID-19, richer and wealthier people will probably still have money to afford progressives. Whereas poorer people maybe can just afford a single vision lens and may be more affected by COVID-19. I think we will see continued growth in high-index lenses, we will see continued growth in multiple layer AR coatings and we will probably see growth in blue light cutting. Furthermore, we are seeing one strange thing happening in 2020 which is the demand for workplace lenses. These lenses were always very difficult to sell in certain markets in Western Europe, but suddenly workplace lenses are selling quite well. We think this could be due to the fact that people are spending day after day in their houses in front of the computer and are maybe realizing that a workplace lens is a much better lens if you are doing a lot of work, either on the computer or at home in a distance of one meter to four meters.


How exactly do you gather your data?

The method you use is very important. Because if you don´t understand what you are measuring and how you are measuring, then the numbers very often raise further questions.
We are measuring lenses sold to optical outlets – ophthalmic lenses do not include the sales of ready readers and pre-mounted spectacles – and we use the lens data gathered to make an estimate of the number of ophthalmic frames sold by country. This is because normally an optician will order a collection of frames for several months in stock in the shops. If consumers come in and chose a frame, then they decide what lenses should go into it. Therefore, the order of a lens is very much in time with the sale of the frame to the consumer. We always do the research in local currency because otherwise you tend to pick up the variations in value between either the euro or the US-Dollar, but what if you buy your glasses in Turkish lira? Then we split frames into three price categories: Under 100,- euro, under 199,- euro and 200,- euro or more.


Are there particular challenges in collecting the data in individual countries?

The ophthalmic lens data have been researched in five separate studies and I believe that the numbers in most places are very close to reality. We are using the term “close to reality” because when you are studying countries like Indonesia, Iran or India you are never going to find the last lens sold. You can just try to get as close as possible. The biggest challenge we had is not with lenses but with frames. For instance, we worked with a consultant who knew the branded frame market in North Africa very well and when his numbers came back we realized that there was a mistake in those numbers because it turned out that Algeria was the most valuable market for frames in the whole world and we knew that this wasn´t the case. We tried to understand why and the following happened.

People who sell a branded frame tend to look at a segment of a hundred euro or two hundred euro, because that tends to be the prices at which branded frames are sold to the consumer. But they don´t go down to the market and to the cheap shops. But especially those cheap shops sell to 80% or 85% of all people living in Algeria. Because the reality is that the annual income is just over 3,000 dollars. If you divide that by 254 days you can work out how much someone earns per day and there is no way that that person ever buys a branded frame. Because a branded frame would mean 30 or maybe 60 days of work and they still have to put the lenses in it.
So what will they do? They go to their local shops! But very often someone focusing on the branded segments doesn´ t go into the local shops, because it does not interest him or her. So I tried to explain to the consultant: 85% of all frames sold in this country are sold through the local shops and not trough the smart shops in the main street which sell to the very rich Algerians. That was a big problem we had, trying to make people think of the whole market and not just a little segment of the market. In the end the guy actually said “Mark, that was very good advice because the market is so big and I never realized that the prices were so low!”


How has COVID-19 affected your work?

We star ted on the f irst of April 2020 with having all our orders cancelled. After we got over the initial shock we realized that COVID-19 was bigger than we had thought. It was going to stay for quite a long time. So we thought maybe it is good to have a good set of numbers for 2019, which was the last pre-COVID year. Because companies need to do budgeting, they need to do forecasts, they need to make plans and you cannot really plan on the basis of 2020. Then we had to get in touch with people, but some didn´t answer their phones, because they had business phones but they were not working at that time. So we needed to find new ways to contact the people through social media, at home and so on. But then it worked very well, because a lot of people were at home and they had time to talk to us and were very interested.


How did you measure the influence of COVID-19?

For the bottom-up method we asked consultants in each country in May and June to use a color for the year 2022. And we said: “If you think the market is going to have growth give us green, if you think it is going to go down give us orange or red” and so on. The system was simple. At the end of August we went back to them and we asked them to check their color again. It was interesting that especially in some countries in Europe we got changes in the color because people had seen how the markets had recovered. Furthermore, we used a top-down method. We looked at the data and we said, let´s see what we know about the coronavirus on a country by country basis. A country like Malaysia is less affected by the virus than a country like Austria and we asked, what´s the economic impact of COVID-19?


What are the main differences?

The United Arab Emirates have not had that many cases of COVID-19 but they have a lot of expatriates. Their families have gone home because it is very expensive to have medical treatment in the United Arab Emirates or they haven’t had their contracts renewed and the permit visa is linked to the work contract. If you don´t have a work contract you need to go home. If you look at New Zealand, exactly the opposite happened. There are about fifty to a hundred thousand New Zealanders working in top jobs in the world who have either moved back or are planning to move back to New Zealand during the period of 2020 or 2021. The reality is: if you have lost your job as a banker in New York, then you may decide to go home or maybe your wife says to you “look we earn 300.000 dollars here in New York, the quality of life especially for our children is not that great with COVID-19, but in New Zealand they have done a fantastic job with controlling the coronavirus and even if we only earn a hundred or fifty thousand dollars, the quality of life may be much better at home. So there have been countries that have had a positive effect from corona.


What are you currently working on?

In December, SWV started working on new projections by country for 2022. The reason for doing this is that significant changes have taken place since September 2020: vaccines have now been developed and are being used. Mutations of the coronavirus, which are more contagious, have been found in South Africa, Brazil, and the UK. Many countries in Europe have now entered a strict lockdown. A new president of the USA has been elected, who may inject significant sums of money into the US economy. The economy of China grew by 2.3% in 2020[1]. For these reasons, we are preparing new projections for 2022, which can be compared with the initial projection of September 2020. These projections have been prepared following direct contact with all 63 countries in the study. These 63 countries made up 94% of the world in 2019.


Is there anything else you would like to tell us?

There is one thing we didn’t cover and which is something a lot of people in the optical industry never think about. We always tend to think about progressives or individualized progressives, about all the lovely frames we produce and all the wonderful methods we have. Magazine covers and articles in trade journals like yours are full of theses high-end products. But at the end of the day we are probably just talking to 70% of the world. Because there are a lot of of people in the world who do not earn much money and who can never afford those spectacles – that is something that really concerns me.

Thank you for the interview and these uncomfortable but true words. ◆
[1] Source: Statista (preliminary data published by the National Bureau of Statistics of China).

How eyewear goes green – within the realm of the possible

How eyewear goes green – within the realm of the possible

Today every company is talking about becoming sustainable. That is the future. But it is also a demand that many consumers – especially from Europe – and many governments are now making. However, entrepreneurs consider some “green” demands to be unrealistic.
But how does a viable way of making the global frame and lens production more sustainable look like? MAFO has spoken to an expert who knows the eyewear industry like the back of her hand and who leads the way forward into a green future. By Hanna Diewald



How can the optical industry work sustainably and economically at the same time? What is the best place to start as an entrepreneur? Where do you get sustainable raw materials for glasses and how do you differentiate “greenwashing” from really meaningful campaigns? Lene Bille Hoegh knows the answers to all of these questions. She and her husband ran an international eyewear company for years before she decided to found the sustainable consulting agency GreenOpticalPlanet, out of personal conviction. Today their team consists of industry veterans who specialize in advising optical companies on how they can become more sustainable. Bille talked to MAFO about the opportunities and pitfalls of sustainable production and her appeal to the industry to find a sustainable recycling system for demo lenses.


What is your philosophy at GreenOpticalPlanet (GOP)?

Our focus is on the client´s sustainability objectives. We are here to help fill the gaps. Most companies already have their own networks but maybe they need help with more suitable, sustainable raw materials or certificates, or maybe they need the overall view of the United Nations sustainability goals relating to their own strategy. We assist where needed, whilst not staying on board longer than necessary. Our aim is to help the clients move forward and then let them move on to their own green path.

From left to right: Lene Bille Hoegh, Clark Sui Wonders and Michael Jardine.

Our personal GOP philosophy is to try to do quite impossible things within the realm of the possible. There is no 100% sustainable eyewear solution yet, however, by piecing the options together as they are introduced in the market, even helping them emerge, we believe that eventually you will reach some fully sustainable and at the same time truly scalable options.

The planet increasingly needs all of us to change the way we manufacture, transport and consume goods, and this needs to happen sooner rather than later. At the same time the eyewear industry leaders have not really hurried to find green solutions; other industries have lead this way before the eyewear industry.
We think the reason for this is less about unwillingness to change, and more about not knowing where to begin. Therefore we really need people, who actually know the eyewear industry, to band together regarding the sustainability aspect. The future needs sustainable fashion – and the consumers in Europe are asking for it loudly.


How “green” is the eyewear industry already?

Image by Comfreak auf Pixabay

I think everybody in the eyewear industry has started to think about sustainability, but not everybody has implemented it yet. We are still in the beginning of the process as an industry. There are many aspects to a fully sustainable product range. Our experience is that after companies have taken the first few steps, most come to a halt. Many start with greener packaging or sustainable measures at their retail locations. The next step for these companies would be to look at raw materials, manufacturing and freight. Or they have already implemented one type of biobased or recycled raw materials, but have not looked at their storage or retail aspects.
Often it is not unwillingness that keeps a company from taking the next green step – they are simply not confident about which crossroads to take. Should they go with recycled, recyclable, biobased or biodegradable? Each of these choices has their own host of challenges as well as the design and manufacturing processes and locations that need to be taken into account.

The European governments have already taken lots of regulatory steps and the European consumers request more sustainable products, and this forces us all to look for more sustainable solutions. If you look at the North American markets, there are still only lesser parts of the consumer segment and only partial government regulations that cater for change, while other parts of that market are trying to keep the status quo.


If you are trading into the Asian markets, then there are very specific minority groups that are requesting more environmentally sustainable products. In Asia it is actually the governments that have really started to look towards sustainability demands and regulations, as they are looking from a manufacturing point of view, first of all. For example, China issued the “Made in China 2025” report, in which they ask the manufacturers to start producing greener in China. One issue here is that parts of the manufacturing base will just move outside of China, and thus avoide change for another handful of years.
The current global drivers for green change are consumer demands and governmental regulations, and we are seeing both demands emerging more and more strongly. At GOP we urge the third driver, which is the industry leadership, to drive this change and create the sustainability demand from within as well.


What is the biggest challenge for most companies on the way to a sustainable production?

There are challenges and blockers. In our experience the greatest challenge is to have a clear long term plan that will still serve your company´s objectives in 1-2-3-5 years. Another big challenge is the protection against “greenwashing”. This includes the choices of certification, the insight into carbon offset, and the assurance that the chain of custody is not compromised. In our experience the real blockers for many are the restrictions with sustainable raw materials, design processes and manufacturing processes. Considerable compromises have to be made regarding ability, quality and cost compared to the conventional materials and manufacturing processes.

This also requires careful consideration, so that the company chooses the material that supports their type of product best. In our experience choosing the raw material is the key, and so is choosing the best suited manufacturer for that material. The manufacturers are not all alike when it comes to getting the most out of an alternative raw material. That said, there are better and better sustainable raw materials introduced to the market all the time. In particular the chemically recycled materials are promising, as they hold no quality and process restrictions compared to conventional materials, their challenge is the cost structure instead.


Could you please explain the term greenwashing?

The idea of greenwashing is that something looks good and green, but when you look deeper into it, it is not. That means, for example, that somebody simply claims that something is green and when you check the chain of custody you discover – it is just a lie. That is the worst kind of greenwashing.
Another example of greenwashing is when companies try to do good things but they are actually not sustainable, even though they were meant to be, for example ocean-plastic frames. There are wonderful campaigns for eyewear that is made of reclaimed fishnets and ropes, but the production process is often very carbon dioxide and water consuming, and most of the end material does not have the quality you need for eyewear, which creates double waste. In general you end up spending a lot of resources trying to extract and recycle the plastic and then you have to discharge maybe 50% – 70% of the recycled material, because it is not good enough. Basically you end up with a product that is a beautiful idea, but it just doesn’t work.
If you want to go that route it is just smarter to join forces with one of the organizations that work in cleaning up the oceans and simply pay them an amount for each frame sold. That will have a truly efficient impact on the environment.


Which raw material do you recommend the most?

The pros and cons depend on where you are placed in the value chain. At GOP, we currently tend to promote recycled raw materials more than anything else. Because for most companies in the eyewear value chain that is still the most manageable option. For a manufacturer or an optical company, the natural first choice is to transition to raw materials that are already recycled, and to produce recycled-content product and offer this to their consumer. This is what we consider a quick win. This way you have already taken your first step towards sustainability, without having to revolutionize your whole business.
The raw materials we recommend have a relatively low carbon footprint, and we also check whether they are ethical. That is important because you can also get recycled products that actually have a higher carbon footprint than a conventional product. That is not really green!

For an international retail chain or for a trade organization, for example when we talk about demo-lenses and central labs, looking at producing products from conventional raw materials and concentrating your effort on creating recyclable loops post-consumer is a very necessary – but also a much longer – strategy, because it has to be done on a bigger scale, in order to be financially and carbon offset sustainable. It requires taking back infrastructures and localized recycling systems, so it is a much slower win, but also one with a much larger impact when it is finally implemented.


What do you think about biodegradable and biobased products?

This concept of biodegradable has many interpretations. Most biodegradable claims still require a particular environment in order to actually degrade. Instead, a solution would be to work with recycled materials or indeed with materials that are biobased, from simple wood to the more complex processed natural materials. But you still need to consider carefully. There are several levels of sustainability just within the term biobased. For example, you can think you are choosing sustainably when you use castor oil based raw materials, but only some of the castor oil plantations are sustainable, others have taken their acreage from rainforest, in which case it is not really sustainable.


Which are the most important aspects that should change in the optical industry in order to make eyewear more sustainable?

1. There is a truly desperate need to develop both sustainable demo lenses and spectacle lenses, with a clearness, hardness and price that can keep up with traditional products.
2. There is a need for a motivation from the heart to invest in research and develop much better alternative raw materials.
3. There is a need to develop a design ethos that constantly challenges use of material, ratio of waste and also of weight and space for transport. 4. There is a need to understand the differences between recycled and recyclable, and setting up workable loops for both. Recycled is pre-consumer, so we are talking about raw materials and manufacturing scrap programs, whereas recyclable products are on the retailer and the consumer side. For retailers there is a big task ahead in not creating the same level of unsold returns and also in learning alongside their consumers how to consolidate take-back systems that work. 5. In the end everybody has to understand that we probably won’t get eyewear for one and a half dollars anymore.


What should and shouldn´t companies do in general?

No company should work with partners who don’t comply to local and international compliance rules. This goes for clean water, filtration, energy, work ethics, quality or wages. You need to know if the people or companies you work with follow the local standards or not, and if they are committed to even going beyond local standards.
Besides that, when you talk about the manufacturing part of our industry, then the most important thing is that it is certified, because in a good certification program most or all of these things are taken into account, and companies should look to enroll and create constantly better trade standards.
If you are a volume product business and you produce and distribute fast fashion products for a very price-sensitive market, your first step probably would not be to look on the life cycle or responsible consummation. But you can still look to the United Nation´s sustainability goals number six, seven and eight. These goals are about protecting the environment. You can work with how much water you should use, how much carbon reduction you can achieve, and how you can choose different, greener raw materials.

If you are a premium product business, you can do a lot for sustainability in one go. The consumer will see those glasses/brands as an investment, and they normally keep the product for a longer time. Your initial price point is higher, and you can either absorb more cost for sustainable work, or you can even promote sustainable consumption and raise the price for the consumer.


Is it also more sustainable to produce and distribute eyewear locally instead of, for instance, producing in China and selling frames in the USA?

If you produced everything you bought next door, then you would be “hyper green”, but that is not the way things work. It is not financially sustainable. The environment is not the only aspect of sustainability, economic viability and social equity are also important.
There is no problem in making a premium product nearby because you can price up and you can sell it, but if you want to produce higher volume products, then either the consumer has to be willing to pay more or you have to do it in places that work and that also feed families. So, sometimes your best option is to do it in Asia.



What can lens manufacturers do?

For me this is one of the areas where more research and development is required. If you are one of the bigger organization within lenses, than you can definitely invest into research. There are a bunch of big companies that are really investing and trying to find solutions.
And if you have a small business, then you can still put a greener option for your customers into your portfolio. But be very transparent about any issues, for instance when the lenses scratch easier or they are less clear or cost a little bit more. Because those are some of the issues, concerning the options that are in the market right now.
The most important thing is to be ready and willing to try. Just understand that sustainability is the way it is going, and you don’t have to wait before getting on board.

The lesser issue for me is prescription lenses, because they have a longer life. The first and bigger issue is demo lenses, because labs and opticians take them out and throw them away. Demo lenses mainly end as waste in landfills, or have downcycle programs that are too complicated and costly. It is important to find an infrastructure for the central labs. To find a way to send the demo lenses back into the value chain and recycle them, either chemically or manually. Be it into new demo lenses or another product.
Creating take back programs and recycle programs requires optical companies, trade organizations, organizations like our own GOP and maybe even raw-product manufacturers, to all band together with the big retailers, and create infrastructures with pick up points for the central labs. This level of sustainability is not a commitment you onboard alone. It really requires that everybody works together.

Thank you for the interview. ◆



In early 2019 Michael Jardine, Lene Bille Hoegh and Clark Sui Wonders started the consultant service GreenOpticalPlanet. It is their belief that the best possible legacy will be to work to assist all companies in evolving to be environmentally friendly and to support the people involved to become responsible citizens of the Earth. Co-founder Michael Jardine started in the eyewear industry in 1980 as a founding partner of the Canadian TannerEye leather eyewear factory. He moved into developing and exporting high quality eyewear in Japan in the late 80´s and operated as a manufacturer´s agent in the early 90’s in Hong Kong. In 2000, he founded Mondottica, his own eyewear company, developing and distributing licensed fashion brands throughout the world. In recent years, since Michael and Bille, his life and business partner, prepared to exit Mondottica, it has been their wish to give something back to the industry that has been their home for many years. They teamed up with their business partner from the industry, Clark Sui Wonders, and founded GreenOpticalPlanet.



Born out of necessity

Born out of necessity

How a company combated the Corona Virus –

a personal report by Norm Kester

For us in the United States, everyone of certain age remembers exactly where we were and what we were doing on September 11, 2001. The memories of that day and the following weeks are forever etched into our memories. I didn’t live through many of the past events that previous generations had etched in their memories: The Great Depression, World War II, and so many others. The Corona Virus Pandemic is just such an event. I remember watching it unfold. Thinking that this was another Ebola or SARS. That this was an event in another country. Another place. When we were leaving for Italy, on our way to Mido, and the event was cancelled, it got real.
By Norm Kester

In days, it was known to be in the US. Then people started dying in Seattle. There was an epicenter near our daughter’s house just outside of Seattle. She, and her husband, came to visit us from Seattle as this was unfolding. They stayed for a couple of days and then headed home. On their way, they got sick. Then we got sick. We quarantined ourselves and got a COVID-19 test. A swab up the nose in a drive-thru testing facility and a quick negative for Flu A and B. We were told to stay put in our house until the COVID results came back. We started feeling better at day 4. Day 10 we got our results. Negative. As we watched things start to unfold around the world, and we began to watch the US shut down, I became filled with the impatience that comes from things being out of my hands and out of my control.


Spring into action

From my home, I started researching everything that was known about viruses, enveloped viruses, bacteria, fungi and a variety of other microbes. As I learned (thank you internet!) everything I could, it became quite clear that this was something that I could contribute to, that Quantum could contribute to. I quickly found the 222 nanometer light invention that could kill virus and bacteria in the air. I sent that information to everyone I knew in government, the medical community, and my friend and colleague networks.

At this time, as I was researching all of this (this was over a two day period), it occurred to me that I had not reached out to any clinics, hospitals or doctor’s offices in our local area.  That day, before I returned to work from my quarantine, I emailed the presidents of our two local hospitals, sent a LinkedIn message to the head of our Urgent Care chain of clinics, and called my general practitioner.

The next morning in my office, I received a call from Brad Converse. He explained that he too was trying to get into this fight, that he owned a company making custom golf putters and was an engineer. He wanted to create a group called “The MacGyver Group” to assemble engineers, businesses, doctors, nurses, 3D printers, and sewists to work to solve whatever issues we could. He set up a Slack channel, and I quickly joined in.


Everybody worked tirelessly

Quickly, Quantum was knee-deep in making hand sanitizer and spray disinfectant to meet the needs locally. We worked on ventilator issues at the hospitals. We worked on creating replacement HEPA filters… there was a worldwide shortage. PPE of all types were running out.

The Quantum team making hand sanitizer. Source: Quantum

We worked with friends and other businesses to create isolation gowns, and a friend quickly repurposed his company (normally making medical knee braces) to make isolation gowns and parts we needed for face shields.

People were sewing masks, and 3D printers were printing face shields. A local company, which normally made X-ray film, made the shields – 80,000 at a time. We at Quantum volunteered to operate as the central hub to sanitize and sometimes sterilize things being made in the community before they went into the hospitals.

I am so proud of everyone at Quantum. They worked tirelessly. Our whole company pivoted in just a few days to work on whatever the hospitals needed. Pallets of hand sanitizer and spray disinfectant started going out. The sense of urgency around everything we were doing was incredible. People were dying.


The ecomomy collapsed but the MacGyver group met daily

All the while, we kept everyone employed. We were burning through cash like crazy. The economy was completely closed. Our sales went to 10% of normal, and companies weren’t paying their existing payables. This wasn’t sustainable, but we committed to ride it all the way to the end together, unified as a team driven with purpose, to do everything we could until we had to close the doors.

Emotions were high. There were hugs and high fives, but there were also tears, worry and fear. We met with everyone every day. We shared what we knew as leadership. We met with the hospitals and the MacGyver group daily.

Tensions in the hospitals were high as well. The PPE shortage was a crippling problem.  Though the MacGyver group was able to solve some crazy problems and most of the PPE issues, isolation gowns and N95 masks became major problems to be solved.


A plan arose: UV-C should kill the virus

During this time, I became more and more convinced to use UV-C to kill (inactivate is the correct, scientific term) the Corona Virus. I had read every paper I could from the Centers for Disease Control and Prevention, the National Institute of Health, the World Health Organization the Food and Drug Administration and any other reputable source on how to reuse N95 masks.

Several of these papers were written during the Ebola and SARS outbreaks. During these events, global pandemics became apparent and emergency preparations and studies were conducted. Vaporized hydrogen peroxide and UV-C rose to the top.

I spoke to several of our engineers about the idea and what I had in mind. Together, we hatched a plan to buy some toaster ovens or microwaves and retrofit them with UV-C bulbs and create some prototypes to test the effectivity against the Corona Virus. We discussed it on Friday, and by Monday we had our first prototype.

The toaster prototype. Source: Quantum

An early microwave prototype. Source: Quantum









The engineering team jumped in with both feet. Very quickly they discovered testing and measurement effectivity cards, dosimeters, and how much energy it took to inactivate just about every microorganism on earth. We showed the hospital our prototype and our calculations and measurements. The hospitals were already familiar with UV-C; they even had dosimeter cards that they used when working with UV-C. The main problem was still how to disinfect at the scale that was needed. Thousands per day were the projections. Our little toaster ovens wouldn’t do the trick. We would need thousands of them and fast.

The final product: FusionUV. A 254 nm light germicidal UV-C disinfection unit.

I decided to send our little toaster oven off to have it tested. I wanted to test it against the actual Corona Virus, but all of those laboratories were consumed by other efforts. We found, through some great friends and colleagues, a testing facility at the University of Tennessee. They agreed to test against other, similar viruses.

On the MacGyver Slack channel, we had ready access to emergency room doctors, infectious disease specialists, respiratory therapy doctors, frontline doctors, surgeons and a whole host of others. We discussed and brainstormed how to solve this issue quickly. I proposed a shipping container with UV-C bulbs. I found a procedure from the University of Nebraska and they were disinfecting entire rooms full of N95 masks. There was hope that we could do this in large numbers.


Desinfection in a shipping container

The next few days saw a few events that propelled this further. The hospital had been using vaporized hydrogen peroxide to disinfect masks, and that night all of the masks failed fit tests after the disinfection. This was a dramatic turn for the worse. Then, a company called Battelle was awarded emergency use authorization for their shipping container solution using vaporized hydrogen peroxide to disinfect N95 masks. Suddenly, UV-C in a shipping container was a major priority. That day we decided to buy a shipping container.

Cargo trailer disinfection unit. Source: Quantum

Over the next few days, the hospitals decided to put one at each hospital location. We then had to buy 2 more shipping containers and get to work on making them. The problems and logistics we had to overcome were too numerous to list here, but we did it! In just three weeks, we went from concept to our first shipping container. We would be able to disinfect 84,000 N95 masks per day.

I started our team on taking the toaster oven concept and making a real device out of it.  They started to design and model it. They quickly built a prototype. We put the device out to bid. We wanted to follow our normal manufacturing method and make it in Oregon. Many things fell into place that normally would not. Many businesses were closed or had no business coming in the door. We found a great partner that could bend all the aluminum we needed. Logistics were a major issue, but we were not going to be stopped.

We received the Payroll Protection Program funds! This gave us the lifeblood we needed.  We knew we would get through all of this. Just as we approached our last two months of operating cash, the federal money hit our account.

Then our test results came back from the University of Tennessee. We had done it! We inactivated the virus. Not only that, we were successful at fully removing the virus from an N95 mask! This was quite an accomplishment.


But I still wanted more …

I wasn’t satisfied with the results. I wanted to actually inactivate the Corona Virus that was responsible for the pandemic. Through connections and relationships, we found a BSL-3 (Bio Safety Level) that was working with the actual Corona Virus.

We started talking to retailers, optometrists and manufacturers and labs about the UV-C solution. We learned a lot about what they were facing and the rules and regulations coming their way.

I wasn’t getting much sleep during this period. My recollection of how exactly we got connected to some Luxottica folks is unclear, but I do know that they were very involved in Italy and offered to test our device with the actual Corona Virus, SARs-CoV-2. We didn’t have our results back from our new test facility. We jumped at the opportunity and sent several of our UV-C devices to Italy.

We continued to meet with our people daily, we met with the hospitals daily, we met with the MacGyver group daily and we continued to disinfect and sterilize objects going into hospitals for emergency use. I met many great people during this time. I learned how to use and program a respiratory ventilator. I tested ventilator manifolds. It was a crazy time.

Our people at Quantum jumped in with both feet. We did so much as a team during this time. These people were amazing. There was never a moment where there was doubt. We just attacked each obstacle.


A new company was born out of necessity

Our team ended up making the FusionUV, a 254nm light, germicidal UV-C disinfection unit.  We have now shipped thousands of them all over the world to inactivate the Corona Virus.  We have now tested it against all sorts of microorganisms. We’ve inactivated or killed them all. We scramble the RNA or DNA of these microorganisms. They don’t have a natural defense to this wavelength of light. Our atmosphere filters it out.

We’re now making different sizes. We’re making rugged units. We continue to test with every germ we can. We continue to learn and improve. We’ve started a new company just to make and explore new ways to use UV-C. It’s called Boon. Not just because of the definition—a thing that is helpful or beneficial—but because we wouldn’t have made this device if it wasn’t needed. If we hadn’t had a Pandemic. It was born out of necessity.


Norm Kester, President of Quantum Innovations.

Norm Kester

Norm Kester, the President of Quantum Innovations, Inc. since 2002 has dedicated himself to manufacturing AR and mirror coating equipment for the ophthalmic industry. The entrepreneur steers his company according to the principle ‘attitude of servitude’ because he firmly believes that it benefits all parties involved in business together.  This year he was awarded for his contribution to the advancement of the optical industry with the 2020 Goodfellow award by the California Lab Committee.Before founding Quantum Innovations, Kester served as Vice President at Satis Vacuum of America. He studied Optical Thin Film Coating Technology at the University of Rochester and received further training in the US Navy Advanced Electronics Program.






A driving simulator as a tool for benchmarking optical lenses

A driving simulator as a tool for benchmarking optical lenses

Pixabay:ID 12019

Conception of the Aalen Mobility Perception & Exploration Lab (AMPEL)

The Aalen Mobility Perception & Exploration Lab (AMPEL) is part of the Competence Center “Vision Research” in the Innovation Centre (Inno-Z) at the University of Applied Sciences in Aalen, Germany. A virtual research environment was developed there, which allows for night driving experiments under highly standardized conditions. This also allows for benchmarking optical lenses.
By Judith Ungewiss, Michael Wörner, Ulrich Schiefer

About one third of all road traffic accidents occurs at night. This seems to correspond to the percentage of the dark period on a superficial view. However, taking into account that only approximately 25% of the yearly mileage is driven at nighttime, the risk of a traffic accident with a fatal outcome is increased by about 50 % at night in comparison to the same distance traveled during the day (data collected for the Federal Republic of Germany) [1][2]. Nighttime driving ability is therefore of specific importance in road traffic.
With regard to the effort involved in setting up a driving simulator, the question as to whether this is worthwhile in order to determine the ability for night driving arises. In this respect – even though we feel that the value of each human life is “inestimable” and thus cannot be quantified in monetary terms – it should be noted that the statistical value of a (traffic) accident death in the Federal Republic of Germany is estimated at an average of about 4.5 million Euros [3]. In comparison, the costs for driving simulator experiments, which in the best case contribute to saving human lives in the future, seem manageable and legitimate. Furthermore, such a simulator has the important advantage to display scenarios in a highly immersive way under standardized conditions (cited as in [4]).

Setup and interior of the Aalen Mobility Perception & Exploration Lab (AMPEL)

The Aalen Mobility Perception & Exploration Lab (AMPEL), operated by the Competence Center “Vision Research” in the Innovation Centre (Inno-Z) on the campus of the Aalen University of Applied Sciences, was launched in 2015 and consists of two large laboratories with associated measurement and workstations.

The nighttime driving simulator situated in the AMPEL lab contains a completely retrofitted Audi A4 (Audi AG, Ingolstadt, Germany) with a steering and pedal unit (SensoDrive GmbH, Wessling, Germany), and two fully digital displays (instrument panel and navigation monitor). Two high-performance projectors (Zeiss Velvet 1600, Zeiss AG, Jena, Germany), which are commonly used in a planetarium environment, project the driving route on a cylindrical 180° screen with a radius of 3.20 m. A monitor (KD 65 XF 9005 BAEP, Sony, Tokyo, Japan) behind the trunk of the car provides an almost realistic scenario through the rear-view mirror. A vehicle can be brought into the laboratory via a sliding window and, if necessary, be exchanged for another vehicle or another test arrangement (see Fig. 1 and Fig. 2). Driving scenarios are imported using the SILAB simulator software developed by the WIVW (Würzburg Institute for Traffic Sciences, Veitshöchheim, Germany). It is possible to visualize traffic routes using existing GPS data.

@image: Fig.1 hier

@image: Fig.2 hier

Speed-related driving noise can be generated by a loudspeaker (BeoPlay Beolit 15, Bang & Olufsen, Struer, Denmark). This noise acts as an acoustic feedback and therefore supports the patients with regard to velocity control while driving.

Calibration procedures are regularly executed prior to the start of a study (Spectroradiometer CAS 140 VIS/UV, Instrument Systems GmbH, Munich, Germany and Minolta Luminance Meter LS160, Konica Minolta Holdings K.K., Tokyo, Japan).

@subhead: Simulator vs. on-road experiments
Why are experiments not directly implemented in the form of (real) on-road driving, but instead a simulator is set up with a great deal of effort with the aim of creating a driving environment as close to reality as possible?
The main reason for this is the complexity and thus usually inadequate standardization of the on-road experiments: It is almost impossible to realize identical conditions with respect to the road surface, weather, lighting, wind conditions etc. for several experimental runs (which may additionally also be executed on different days). The personnel expenditure for on road experiments is also considerable: On the routes used, the street lighting may have to be switched off, and the routes must be locked by roadblocks or supervisory staff so that passers-by do not endanger themselves or the experiments. Additionally, for insurance reasons, such experiments are only permitted in a vehicle with a dual brake system set under the constant supervision of a driving instructor. Experiment supervisors and operators (responsible for the technical implementation of the experiments) are required.
On the other hand, only one test supervisor and one operator are required to carry out the corresponding experiments in a simulator. A driving simulator allows for highly standardized examinations without compromising the safety of test persons [4].

@subhead: Technical and experimental opportunities
The driving simulator in the AMPEL laboratory realizes the determination of visual acuity and contrast sensitivity also while driving. Individual local thresholds are assessed by eight-position Landolt Cs. The stimuli can be presented at various locations under different distances within the setup:
• at the projection screen (right road side, 4.66 m)
• at the monitor just behind the trunk via the center of the rear-view mirror (3.40 m)
• at the center of the navigation monitor (0.75 m)
• at the center of the instrument panel (distance 0.72 m) (see Figure 3).

@image: Fig. 3 hier

The appearance of the visual signal can be announced to the test participant with an audio signal. The opening of the appearing Landolt C has to be indicated (verbally) by the test person and is recorded by the test supervisor or – as an alternative – by a miniaturized microphone. In this way it is possible not only to check the correctness of the respective response but also to record its latency. Beyond Landolt Cs, obstacles (e.g. pedestrians or animals, each with various contrast levels) can be presented.

The simulator is equipped with an eye tracking system (SmartEye Pro, sampling rate 120 Hz, gaze accuracy of 0.5° under ideal conditions, SmartEye AB, Gothenburg, Sweden), which enables the contact-free recording and evaluation of head and eye movements. For this purpose, the driver is observed via (a minimum of) three infrared cameras while driving. The driving scenario is recorded by an additional scene camera. With the help of this set up, head and eye movements as well as fixations of the driver can be assigned and annotated to certain objects or regions of interest.

A realistic display of glare, for example from headlights of oncoming vehicles, is an essential factor for the representation of a close-to-reality driving environment. Simply projecting virtual headlights on the screen of the simulation environment does not achieve the necessary luminance values. Instead, a patented mobile glare device was developed for the AMPEL laboratory: With the help of cable robots, wireless LED arrays controlled via WiFi are moved in both, horizontal and vertical directions. The power supply is provided by small lithium-polymer accumulators, as used in model aircraft constructions [4].

In order to validate such a simulator, it has to be determined whether a virtual scenario actually measures what it is supposed to measure. Such validation is achieved by comparing the simulator results with those of a real on-road driving test under comparable conditions.
At the AMPEL lab, the on-road parcours of the “Burren” campus at the Aalen University, next to the driving simulator, is transferred into its virtual environment by using the Software package SILAB (Würzburg Center for Traffic Sciences, WIVW, Veitshöchheim, Germany) [4].

@subhead: Benchmarking optical lenses
Optical lenses are usually evaluated by ray tracing methods or questionnaires: Ray tracing is well suited to characterize the image quality at the retina level whereby the image processing in the subsequent visual pathway is not taken into account. Questionnaires are subjective tools with an inherent lack of standardization.

A new, patented approach was set up at the AMPEL laboratory: A psychophysical test records the individual’s visual performance or impairment in a location-specific manner within the highly standardized environment of a driving simulator. LED arrays that are either static or moving via cable robots serve as glare sources [5]. Static and dynamic optotypes, moving along so-called vectors with a constant angular velocity, are presented for this purpose. The vector origins can be placed within the center of a glare source (current setup: Visual angle: 0.3°, luminance level 60 kcd/m2, 6.2° left of and 1.1° below the fixation mark, corresponding to the left headlight of an oncoming car [GOLF VII, Volkswagen AG, Wolfsburg, Germany]). By this way the individual, location-related extent of the visual impairment due to halo or starburst can be assessed (see Figure 3). Local threshold variability and individual response time are assessed by repeated presentations and vector placements within unaffected visual field areas on meridians 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° (in random order).
The extent of the displacement of the isopters during the glare condition, compared to the initial condition without glare represents the magnitude of impairment due to glare / halo size (see Fig. 4) [6]. Patient responses can be recorded in order to extract reaction times either from these recordings or from the keypad inputs.

The setup is being used for characterizing the visual effects of media opacities (cataract) in motorists (ContrastVal study, Identifier: NCT03169855) for benchmarking the impact of any kind of optical corrections, such as intraocular lenses (JJ-EYHANCE study, Identifier: NCT04059289), spectacle lenses, contact lenses, or other (surgical) refractive procedures.

@image: Fig.4 hier

@subhead: Conclusions
In the AMPEL lab, a virtual test environment was created which allows for night driving experiments under highly standardized conditions. By means of visual acuity or contrast vision testing under static or dynamic conditions and at various locations, benchmarking optical lenses can be achieved. In addition, static or dynamic blinding of the test subjects with simultaneous time-resolved visual function testing is possible. In comparison to real on-road experiments, simulator experiments are safe, well-standardized and require a comparatively low effort. A validation is possible if required.

[1] Kraftfahrtbundesamt. Erneut mehr Gesamtkilometer bei geringerer Jahresfahrleistung je Fahrzeug. Updated April 18, 2020. Accessed April 18, 2020
[2] Statistisches Bundesamt (Destatis). Verkehrsunfälle Zeitreihen 2017. 2018
[3] Spengler H. Kompensatorische Lohndifferenziale und der Wert eines statistischen Lebens in Deutschland. Zeitschrift Arbeitsmarktforschung 3:269–305. 2004
[4] Ungewiß J, Schiefer U, Wörner M. Untersuchung der Nachtfahrtauglichkeit im Simulator – Vorstellung des Aalen Mobility Perception & Exploration Lab (AMPEL). Der Augenspiegel 06/2019:38-41. 2019
[5] Eichinger P, Sauter T, Schiefer U, Schmitt U, Ungewiss J, Hirche M, Schuster M. Fahrsimulator und Verfahren zur Durchführung einer Fahrsimulation. German Patent and Trademark Office: Patent 10 2017 126 741, IPC G09B 9/02
[6] Schiefer U, Ungewiss J, Wörner M. Ortsbezogene Quantifizierung von Halo- und Streulichtbeeinträchtigung. German Patent and Trademark Office: Patent 10 2019 121 602 A1, WO 2020/089284 A1

The authors would like to thank Prof. Dr. Peter Eichinger, Prof. Dr. Ulrich Schmitt and their whole ContrastVal study team (Mechatronics, Aalen University, Germany) for the design and implementation of the glare sources and Prof. Dr. Jürgen Nolting and Prof. Dr. Günter Dittmar (AWFE Steinbeis Transfer Centre, Aalen, Germany) for their comprehensive support in light measurement tasks.

Disclosure of financial and proprietary interests:
Ulrich Schiefer is consultant of the Haag-Streit AG, Köniz, Switzerland.
Michael Wörner is Managing Director of Blickshift GmbH, Stuttgart, Germany.


Corresponding author:
Judith Ungewiss –
Judith Ungewiss holds a M.Sc. in Ophthalmic Optics & Psychophysics. She works as scientific assistant in the Competence Center “Vision Research” in the study course ophthalmic optics & audiology at Aalen University.
@image: Judith_Ungewiss

Dr.-Ing. Michael Wörner is a software engineer who works as scientific assistant in the Competence Center “Vision Research” in the study course ophthalmic optics & audiology at Aalen University. In addition, he is Managing Director of Blickshift GmbH in Stuttgart, Germany.
@image: Michael_Wörner

Prof. Dr. med. Ulrich Schiefer is head of the Competence Center “Vision Research” (study course Ophthalmic Optics at Aalen University), which addresses the visual system and its possible dysfunctions, especially regarding the development and validation of examination and therapy procedures. After his medical studies and service in the Dept. of Ophthalmology at Military Hospital Ulm, he joined the University Eye Hospital Tübingen in 1989 where he has filled various positions in a full-time appointment until 2012 and in a part-time scientific appointment up to now. Ulrich Schiefer holds several patents on perimetric examination technique and other mainly sensory physiological examination methods.

Infrared protection for sun protection lenses

Infrared protection for sun protection lenses

The sun

Any reduction of the light spectrum using filter lenses triggers a lot of discussion. Even with UV420 lenses, there are many arguments for and against in the market and some even ask the question whether the lens industry will soon recommend protecting the eyes by not letting in any more light at all. The simple background to this discussion is the continuously rising life expectancy of the population in developed countries and the understanding that for the foreseeable future it won’t be as easy to replace the “worn out part of the eye” as it is, for example, to replace a hip.

By Florian Gisch

While incidences of cataracts and AMD were characteristic of the later years of life in the 1950s, patients affected today are typically in the middle of their lives, possibly in a job and needing their eyesight more than ever to use digital media, smartphones, etc.

Thus all these efforts are simply aimed at keeping the harmful effects as low as possible over the entire lifetime, in order to delay the inevitable onset of signs of wear and tear to as old an age as possible.

Development of sun protection products

After initial suspicions that UV light could be harmful in the middle of the 19th century, Crookes sun protection lenses appeared in 1913, guaranteeing 100% UV light protection. In 1908 the Swiss ophthalmologist Alfred Vogt succeeded in proving its harmfulness. In 1926 he published his conclusions that ultraviolet light has a damaging effect on the eye, pointing out at the same time that infrared radiation was likely to have a similarly damaging effect.

In 1930, the first sunglasses were produced in series, with the main focus still on glare protection. In addition to the fashion aspect of sunglasses, protective standards such as the recently developed EN183 were introduced which speak of complete UV protection as soon as there is absorption of 95% in the range up to 380 nm. The more popular standard – which every end user knows – in the meantime is the UV400 quality seal, which also takes into account visible light and the amount of harmful high-frequency blue light blocked.

Infrared protection has received little attention so far up to now.

Interestingly, the same was true for infrared protection in the field of dermatology until the topic was rediscovered a few years ago. Far from a purely “marketing gimmick”, but from the field of environment-related molecular aging research, the development of sunscreen creams was initiated, which in addition to pure UV protection also offer infrared protection. In this connection, premium manufacturers now often make the claim: “Without infrared protection, you are only half protected against the sun”.

If one compares the proportion of UV light striking the earth with the amount of infrared in the sun’s radiation, the question inevitably arises as to why this topic was not addressed much earlier. There seems to be no point in unnecessarily exposing one’s eyes to heat radiation.

UV-light diagram

Amounts of UV light and infrared light striking the earth due to solar radiation.

According to the findings of the Association for Radiation Protection, wavelengths of light between 780 and 10,000 nm can cause significant thermal damage to the eye. It is important here to make a distinction between work safety protection and sun protection, because the spectrum of sunlight hitting the earth is completely different from that e.g. when working in front of a blast furnace. Thus the relevant area of ​​consideration in this context is the frequency range up to 2,500 nm.

Radiation intensity diagram.

Radiation intensity diagram.

Depth of penetration: What impinges where on the eye?

A significant proportion of the dominant infrared (IR)-A component in sunlight in the range up to 1,400 nm penetrates to the retina. This follows the general rule: the shorter the wavelength of the IR radiation, the greater the depth of penetration. This particularly affects the choroid which can be damaged by IR-A, leading to localized defects in the retina tissue. Only a small proportion of radiation with wavelengths longer than 2,000 nm gets through the cornea. The anterior chamber of the eye absorbs all radiation above 2,000 nm. All wavelengths greater than 1400 nm are filtered out by the lens and vitreous part of the eye.

Spectral transmittance

Spectral transmittance.

Significant radiation in the wavelength range of 400 to 1400 nm can fall on the retina. The infrared radiation energy that the eye absorbs causes it to warm up (Vos and Norren 2004, Brose et al. 2005). The exact mechanism by which long-term exposure to IR radiation leads to clouding of the eye lens (cataract) is still not fully understood (Brose et al. 2005). It is also difficult to distinguish between the fundamentally multifactorial-related development of cataracts and numerous other biochemical changes – in particular changes in the composition of lens proteins with increasing aggregation of insoluble high-molecular proteins – and cellular changes that are genetically modified and are affected and exacerbated by environmental factors (Truscott and Zhu, Michael and Bron 2012).

Not for nothing are certain kinds of cataract referred to as fire cataracts or glassblowers’ cataracts. The effect of infrared radiation on such a condition is difficult to prove due to its development over a very long period and thus it is difficult to setup a test, but it is considered very likely.


A general distinction must be made between the front and rear parts of the eye. Where protection of the lens with regard to sun protection is concerned, the infrared spectrum from 780 to 2,500 nm is of interest​​, whereby the anterior chamber of the eye already offers fairly good protection between 1,300 and 1,500 and above 2000 nm.

Thus the main stress on the lens is in the ranges 780 to 1,400 nm and 1,500 to 2,000 nm. Up to 1,400 nm, IR radiation penetrates to the retina, causing it to warm up.

The well-known reasoning that a reduction in the transmission of visible light (e.g. through standard sun protection of 85%) leads the eye to adapt to the light conditions, thus in the case of lenses without UV protection letting in more UV radiation than untinted lenses, can be transferred 1: 1 to the infrared problem. In other words: wearers of sunglasses without infrared protection expose their eyes to more IR radiation than if they were not wearing sunglasses at all.

As a consequence of increased life expectancy, no opportunity should be missed to limit potentially harmful external influences – particularly on the retina – to an absolute minimum. Ultimately, this is exactly what we have been doing in our industry with regard to UV protection for decades.

Transmission change simulation

Simulation of the effect on the transmission change on the respective medium – black without the coating / red with IR coating.

An IR protection coating on sun protection products reducing the transmission between 780 and 2.000nm to a minimum for providing optimal protection to the lens and the retina is a useful step to differentiate professional sunglass protection products from discounter products by providing additional benefits

It is an added value that can be easily explained to the end user. Ideally, in time it should be recognized with a similar stamp of approval to UV400. Moreover, this additional protection would highlight the distinction between our products and those of the fashion sunglasses industry.