Presbyopia is the gradual loss of the eye's ability to adapt to close objects with increasing age. In the young eye, the refractive power is adjusted by shaping the elastic eye lens through the ciliary muscle. However, with advancing age, the elasticity of the eye lens steadily decreases so that between 40 to 50 years the distance necessary for sharp vision increases to 50 cm. At about 70 years, sharp near vision is no longer possible at all (Picture 1).
Although presbyopia is not a disease but an age-related loss of function, its effects are considerable: In 2015, approximately 2 billion people were affected [1] and thus impaired in their daily activities, such as driving [2]–[6]. Globally, the resulting loss of productivity is projected up to USD 11 billion [7].
Up to now, compensation of presbyopia has only been achieved with reading glasses or contact lenses, or by replacing the natural lens with an artificial intraocular lens within the treatment of cataract. A technical solution corresponding to the natural accommodation of the young eye is still not available.
Previous studies of the research group Pathophysiology of Vision at the Institute for Ophthalmic Research at the University of Tübingen under the direction of Prof. Dr. med. Dr. h.c. mult. Eberhart Zrenner successfully demonstrated that novel contact lens electrodes allow to measure the electrical potential changes of the ciliary muscle during accommodation and to use them to control an artificial lens (Picture 2).