By Eva Chamorro, IOT
FreeForm technology made it possible to have any lens design using just spherical lens blanks, it has increased the possibilities in terms of what can be designed and produced. But FreeForm, by itself, is not equivalent to better quality or performance. In fact, the result is going to depend not only on the calculation technology used for the design in the first place, but also the production quality of the lab that is used to make the lens.
The standard ISO 8980-2 specifies requirements for optical and geometrical properties that power variations lenses should meet. These criteria are based in the verification of lens power in the reference points of lenses without considering other points of the lens surface. However, the quality of the lens in other points of the lens can affect visual quality and visual performance of the user.
Along this presentation, it will be presented the results of a double-blind wearer trial in which a group of users compared the visual performance of a lens with an excellent production and a lens with induced errors during the generating process. Results show the importance of the quality and reliability of the surfacing process of free-form lenses in the user satisfaction.