Presbyopia is a vision disorder that affects most people beginning at about the age of 40. Everyone will eventually experience this condition regardless of past eye health.
Presbyopia is a condition in which the eye is unable to focus on nearby objects, resulting in blurred near vision. People with presbyopia typically have reached middle age and often find themselves holding books, newspapers, and other printed material at a distance in order to be able to read them. People with presbyopia can also experience headaches, eyestrain, and a feeling of fatigue after performing activities that require the ability to see up close.
Presbyopia does not result from injury, disease, or genetic conditions. Rather, it is a natural part of the aging process. With age, the composition of the proteins in the eye's natural lens changes, causing the lens to harden and lose its flexibility. Because the lens normally changes its shape when accommodating proximal points of focus, the loss of flexibility prevents the eye from being able to focus on nearby objects, creating blurry near vision.
Another theory posits that the crystalline lens continues to grow as we age, until it becomes so large that it can no longer change its shape, reducing the eye's ability to focus on nearby objects.
Individuals who have not reached middle age and are unable to see objects up close may have a condition called nearsightedness. Unlike presbyopia, this disorder often results from an abnormality in the shape of the cornea rather than the crystalline lens.
Presbyopia can be corrected through bifocal eyeglasses, which have two separate prescriptions - one to accommodate nearsightedness or farsightedness and another to accommodate the inability to see very close objects. Over-the-counter reading glasses may also be used to eliminate vision defects caused by this condition.
Another solution is multi-focal contact lenses that also feature two prescriptions to accommodate near and distance vision. Other contact lenses are designed to provide one eye with near vision and the other with distant vision. This is known as monovision. Prescriptions for both glasses and contacts need to be updated as a person's lenses continue to lose their ability to focus and thereby further reduce vision.
Certain patients may also choose LASIK surgery to accommodate loss of vision through presbyopia. In the procedure, one eye is corrected for near vision and the other for distance vision. In some cases, patients may only require surgery on one eye to eliminate or reduce their dependence on corrective eyewear.
In order to decrease the need for follow-up procedures due to prescription changes, presbyopic individuals who are interested in LASIK vision correction should wait until their presbyopia has stabilized (usually between the ages of 50 and 65) before undergoing the procedure.
Another surgical option for presbyopia correction is known as Conductive Keratoplasty (CK). The procedure involves the use of radio frequency energy to reshape the cornea in order to allow the eye to focus images properly.