Presbyopia

Ophthalmology includes a condition called Presbyopia. It is an age-related inability to focus upon and clearly see objects that are close. Commonly known as tired eyes, it usually appears between the ages of 40-45. This is a natural physiological alteration and not pathology.

Transmission
The first symptoms are very specific. Objects that are close by appear blurred. To read, text is held beyond the normal reading distance and additional lighting may be needed. This condition affects both myopic people and hyperopes although the later usually suffer from it earlier. It also affects people who have never worn glasses.
 
Causes
Presbyopia is a consequence of natural muscular deterioration caused by aging. The eye has a muscle called ciliary that accommodates the crystalline (ocular) lens so that close-up images are seen properly. The ciliary muscle, as any other muscle, sees reduced elasticity with time and thereby looses the capacity to focus and may cause difficulty in viewing very near objects.

Benefits
At the present time, intraocular lenses are used to correct presbyopia. Treatment with high-end Excimer laser is also available.

Procedure - Corrective lenses:

• Conventional lenses: to correct focusing for close-by objects but not for long and intermediate distances.
• Bifocal lenses: they make it easier to alternate between close and long distance vision. Both are properly focused, near distance by the lower part of the lens and far distance by the upper.
• Progressive lenses: they allow good vision at any distance when varying the position of the head. The structure is like the one of bifocal lenses but without the marked division.
• Contact lenses: they limit the system of multifocal lenses. There are also monofocal contact lenses - one to focus at close distance and the other at long distance.

Surgery
Surgical treatment for presbyopia is not definitive.  Although it has been treated, the ciliary muscle continues to lose elasticity with time. One surgical procedure uses laser technology. A prosthesis implant can also be used (Schachar technique) to recuperate the distance between the crystalline and the ciliary muscle. In some cases, intraocular lenses are implanted.