Refractive irregularities of the eye result in a common clinical condition called presbyopia. As a result, the vision of the eye is hazy and must be clinically corrected, most commonly with spectacles or contact lenses.

Presbyopia

This condition is marked by the incapacity to clearly focus on near objects, is age-related and comes from the Greek term meaning “old man’s eye”. It is almost certain from middle to old age when the focusing capacity of the eyes reduces. As our eyes age, the protein in the lens weaken and becomes hard and less elastic. You may have noticed that many old people hold whatever they read at a distance. This marks the onset of presbyopia and holding the book away reduces the divergence of light and hence a clearer vision. Soon this fails to work and then the only way out is convex reading spectacles.

Some other conditions like diabetes, severe dehydration and overexposure to ultraviolet light may also damage the lens protein and cause presbyopia.

Prevalence of presbyopia

Although presbyopia is related to the aging process, its occurrence varies according to certain geographic factors as well. It is said to occur earlier in people who live closer to the equator. Research has also suggested that ambient temperature rather than latitude causes greater variation in its prevalence. It is said that more the ambient temperature, the earlier the chances of presbyopia. In fact, studies have reported that since the ambient temperatures are usually high in developing countries there are fewer cases of presbyopia, though its occurs at an early age here. Whereas, in developed Western countries 65% of all people who wear spectacles suffer from presbyopia.