Presbyopia definition

Presbyopia is a disorder caused by physiological aging of the intraocular lens. The eye lens gradually loses its plasticity and elasticity, its core gets larger and denser, its lens fibers sclerotize, the lens gains some volume and this leads to gradual diminishment of the accommodation ability which is irreversible.

Even though the sclerotization starts with creation of the eye lens we can observe it only when the loss of accommodation ability causes us problems when perceiving close objects.

The formation of presbyopia is dependent on surrounding temperature and most of all on the age of a person but also on the refractory state of the human eye. In the case of  emmetrope (without refractory disorder) it is approximately after 40^th year of life. In the case of hypermetrope (longsighted) presbyopia originates earlier, in the case of myope (shortsighted) it originates later or in some cases the problems may not appear altogether.

Presbyope usually helps himself by moving the text further away from him, tilting his head back, reading in brighter conditions where his pupils contract. These problems emerge earlier and are more distinctive as far as those people are concerned whose jobs demand long-term concentration on closely located objects..

Presbyopia is actually the loss of accommodating ability which is why we try to substitute it for appropriate converging eye lens so that a person can feel comfortable when working with closely located objects. We can say that the addition needed for normal close vision at 45 years of age is approximately 0.5 – 1 diopter, at 50 years it is 1.5 - 2 diopters and it increases by 0.5 diopter with every five years of age. Due to aging the difference between close vision and far vision can be approximately 2.5 – 3 diopters. However, the progress of presbyopia is individual.