Presbyopia is a condition associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Symptoms include difficulty reading small print, having to hold reading material farther away, headaches, and eyestrain. Different people will have different degrees of problems. Other types of refractive errors may exist at the same time as presbyopia.
Presbyopia is a normal part of the aging process. It occurs due to hardening of the lens of the eye, causing the eye to focus light behind rather than on the retina when looking at close objects. It is a type of refractive error along with nearsightedness, farsightedness, and astigmatism. Diagnosis is by an eye examination.
Treatment is typically with eyeglasses. The eyeglasses used have higher focusing power in the lower portion of the lens. Off the shelf reading glasses may be sufficient for some. Contact lenses may also occasionally be used.
People over 40 are at risk for developing presbyopia and all people become affected to some degree. Around 25% of people (1.8 billion globally) are currently affected. The condition was mentioned as early as the writings of Aristotle in the 4th century BC. Glass lenses first came into use for the problem in the late 13th century.
The first symptoms most people notice are difficulty reading fine print, particularly in low light conditions, eyestrain when reading for long periods, blurring of near objects or temporarily blurred vision when changing the viewing distance. Many extreme presbyopes complain that their arms have become "too short" to hold reading material at a comfortable distance.
Presbyopia, like other focal imperfections, becomes less noticeable in bright sunlight when the pupil becomes smaller. As with any lens, increasing the focal ratio of the lens increases depth of field by reducing the level of blur of out-of-focus objects (compare the effect of aperture on depth of field in photography).
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Journal of optometry : open access