Multifocal glasses are a practical solution for those suffering from presbyopia. However, the technology has some limitations, such as distortions and narrow-width vision. Autofocal glasses claim more field of view and greater visual comfort.
Everyone over 40 on this planet – up to 2 billion people in total – will sooner or later face some form of presbyopia or presbyopia. This insight led Dr. Jelle De Smet (imec and UGent) on the road to an application for the switchable lens he had developed during his postdoc: high-tech eyewear for people who, in addition to their normal eye defect, I am also faced with presbyopia. Together with fellow pioneer Paul Marchal, De Smet founded in 2016 Tomorrow Glasses On. The tech company from Ghent is today taking decisive steps to commercialize autofocal eyewear as an attractive alternative to common multifocal solutions.
The phenomenon of presbyopia or presbyopia is part of a natural aging process, explains De Smet first. “There is a small lens in our eye that can change shape to focus on nearby objects or letters. As we age, on average from the age of 45, that lens loses its flexible ability. Reading a book, looking at a computer screen or reading car mirrors becomes more difficult. “
The most ready-to-use solution for those who also have good eyesight are simple reading glasses. It becomes more complicated if this person already has reduced vision. Then suddenly he needs two glasses. One to look into the distance and another to read the newspaper or the menu. “Today, so-called ‘progressive’ or ‘multifocal’ lenses discreetly combine the two ocular anomalies into one lens,” explains De Smet. “Distant view, central view and reading view merge from top to bottom. Depending on where you look exactly in the glass, you get a sharp image. “
The great advantage of progressive lenses is that the wearer does not have to constantly change the frame. Watch TV, tie a knot or stroll along the scenic coastline: one size. However, there are also limitations to progressive lenses. Due to the wide variation in diopter (or lens power) between the top and bottom, the glass surface experiences distortion visible at the edges. “These optical disturbances restrict the field of vision, both in distance vision and in reading vision. Climbing stairs, for example, often causes problems. A running piece of text can only be read on a limited line length. This is also why progressive eyeglass wearers often visibly move their heads while reading. “
The optical distortions of multifocal glasses narrow the field of vision, both in distance vision and in reading vision.
To counteract this type of inconvenience, autofocal eyewear technology mimics the effect of a healthy lens as closely as possible, explains De Smet. “At the bottom of the glass is a small electrically switchable lens, made of a kind of foil with a liquid made of liquid crystals inside. The same material used in LCD TVs. With the push of a button, some power is applied to the film. The position of the crystals changes and the lens now acts as a magnifying glass. “
Even in off mode, the lens has a function: it reduces the dioptric difference between the top and bottom of the glass. This significantly reduces the distortion typical of progressive lenses, says De Smet. “People who wear autofocal glasses can see better and wider at almost any distance. The switch to autofocal glasses is also less drastic and the adjustment process is much more enjoyable than progressive glasses. “
From an aesthetic point of view, autofocal glasses make as few compromises as possible. “Obviously there has to be room to integrate the electronics, but the glasses also have to look good. The frame of our glasses is inside 3D printed. We currently offer around 160 variants in different designs and colors. In the future we will work even more intensively with specialized frame manufacturers and design houses ”.
The first version of the autofocal glasses was launched in the summer of 2021. In the meantime, the product has passed the pilot phase, confirms Jelle De Smet. “By the end of this year, the prescription range will have expanded to strengths from -6 to +4, which is 95% of all prescriptions.” In line with the price of premium progressive eyewear, the average eyeglass wearer pays between 1000 and 1500 euros for a frame including eyewear. An investment in visual comfort with an undeniable return, according to the technologist.
