Presbyopia

Presbyopia is a condition that occurs with growing age and results in the inability of the human eye to focus on objects up close. Presbyopia is most likely the result of a decrease in the flexibility of the lens of the eye, changes in its curvature from continual growth, and loss of power of the ciliary muscles (the muscles that bend and straighten the lens).

Presbyopia is not a disease as such, but a condition that affects everyone at a certain age. The first symptoms are usually noticed at the age of 40-50. It can start with difficulty reading fine print, particularly if the lighting is poor, or with eyestrain when reading for long periods. More advanced presbyopes may complain that their arms have become "too short" to hold reading material at a comfortable distance.

Presbyopia cannot be cured, but the loss of focusing ability can be compensated for by corrective lenses of the converging type. In subjects with other refractory problems, multifocal lenses (such as bifocal or trifocal lenses) or progressive lenses are used.

See also

• Eyeglass prescription, especially the section on Distant vision and near vision.