Presbiopia
“The arms extend further and further while reading “; patients explain the phenomenon of presbiopia in this way. This is also defined as aged eye. To read the writings of a book, it has to be held at a distance from the eyes and the arms are not long enough most of the time. Presbiopia is a disease related with aging. In the intrauterine life, the eye lens is supplied with sufficent blood by vessles. This supply ends from the time of the first cry of the baby. The lens gradually gets thicker, more compact and dull (just like the peel of the body of a tree it thickens in years). With loss of elasticity, the lens also loses its natural round shape and focuses with difficulty at near objects. Presbiopia is an unpreventable phenomenon. At advanced ages, the elasticity and flexibility of the lens decrease and it loses its ability of accomodation. In addition, the ciliary muscle loses its ability to contract which provides movement of the lens fibers. Presbiopia is one of the natural stages of aging and can not be treated with current technology.
In whom is presbiopia observed ?
Presbiopia symptoms occur approximately after the age of 40 years. It is observed in everyone who passes his/her 40th year sooner or later. The time of its occurence also depends on other factors (including refractive disorders). A person with myopia does not need correction for a longer time compared to a person with hypermetropia, because his/her lens does not have to curve so much for near adjustment compared to a person with hypermetropia. Vision weakness in people with myopia can be corrected with bifocal or reading glasses. People who have never used eyeglasses before need reading glasses. People with hypermetropia feel presbiopia symptoms to a greater extent compared to people with myopia. However, presbiopia never develops suddenly, because it has a slow and long-lasting course. Normally, the first symptoms occur between the ages of 40 and 50 years.
Myopia and Presbiopia
For example, people with mild myopia (approximately between – 2 and – 3 Diopter) always need eyeglasses to see distant objects. They also need these eyeglasses in advanced ages. When they want to read, they can take off these eyeglasses and read without eyeglasses. Mild myopia provides reading without eyeglasses at advanced ages, for distant-sigth (for example, driving, watching TV etc.) eyeglasses should always be used. When present myopia is corrected with operation (for example, Lasik), distant objects can be seen clearly without eyeglasses. Presbiopia occurs in everbody with advancing age and reading eyeglasses are generally needed to see near objects (when looking at the watch, cellular phone or mirror). The vision power for intermediate distances also weakens. For this an alternative treatment is monovision therapy.