Glasses for presbyopia
Presbyopia (age-related hyperopia) is a constant companion of healthy aging of the body. After 45 years, the lens (a powerful natural lens of the eye) loses the elasticity necessary to focus on nearby objects. Some presbyopes have enough reading glasses. But if a person has a refractive error (farsightedness, astigmatism, etc.), then for the correction of presbyopia, the only solution other than surgery is to wear multifocal lenses.
Gordon Wetzstein, an engineer from Stanford University, and his colleagues have created a prototype of autofocal glasses designed to solve the main problem of modern so-called progressive lenses (one of the types of multifocals): to get a clear picture, the wearer must always look straight. This causes inconvenience, including when driving a car. So, in order to look in the side mirror, you will have to take your mind off the road and turn your head almost 90 degrees to the left or right, because progressive lenses have no peripheral focus. Wearing glasses with progressive lenses can also make it difficult to move around the street: such people have a higher risk of falling and injury.
Autofocal glasses work on the principle of a lens: the lenses in them are filled with liquid and change shape from convex to flat when the point of fixation of the gaze changes. Eye tracking sensors detect the direction of gaze and determine the exact distance to the object of interest. For the first time, a group of researchers has developed software that uses data from an eye movement tracking device to keep liquid-filled lenses in constant and perfect focus.
Focusing on near and distant objects when changing the direction of view in autofocal glasses. Source: Robert Conrad, Stanford University press release.
Presbyopic vision without glasses and with different types of correction: progressive glasses, monovision (a method of correcting presbyopia, in which the leading eye is "adjusted" to see into the distance, and the second one is closer, and the brain chooses the "right" eye, which gives a clearer picture), and autofocal glasses when looking at near and distant objects. Source: article in Science Advances.
To test the prototype, a study was conducted with the participation of 56 volunteers with presbyopia. The subjects reported that autofocus glasses work better and faster when reading and performing other tasks. According to the quality of vision, the preference of volunteers with experience wearing progressive glasses was given to autofocal (without taking into account the size and weight of the prototype).
Source: article in Science Advances.
At the moment, the prototype looks like virtual reality glasses, but the authors intend to improve it within a few years, making it lighter, more compact and stylish.
Article by N. Padmanaban et al. Autofocals: Evaluating gaze-content eyeglasses for presbyopes is published in the journal Science Advances.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Stanford University: Stanford develops 'autofocals' – glasses that track your eyes to focus on what you see.