Visual Conditions
Hyperopia
Farsighted Eye
Hyperopia, or farsightedness, occurs when images are formed behind the retina, resulting in a blurred image. This is due to an eye that is relatively too short, or the refractive powers of the cornea and lens of the eye are relatively too weak. Depending on the degree of farsightedness and the age of the individual, some farsighted people may see clearly at both distance and near through the process of accommodation, or focusing of the lens in the eye. This may cause significant eyestrain, however, and accommodative abilities are gradually lost with aging.
Myopia
Nearsighted Eye
Myopia, or nearsightedness, is a condition of the eye in which images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
Myopia usually begins in childhood, and progressively worsens until adulthood is achieved, usually about 18 to 21 years of age.
Astigmatism
Astigmatism
Sometimes the cornea is irregularly shaped, causing the eye to focus an object on two different areas of the retina. This is known as astigmatism. For the cornea to bend light correctly, it should be dome-shaped, like a basketball. Astigmatic corneas are shaped more like a football. This causes a distorted view when looking at objects which are close-up and far away.
The cause of astigmatism is unknown. Astigmatism is often associated with myopia or hyperopia, and usually occurs from birth. It may be hereditary, or it may be caused by factors such as pressure on the cornea, incorrect posture, or increased use of the eyes for "near work."
Mild astigmatism usually doesn't need to be corrected. Eyeglasses, contact lenses, or refractive surgery can correct moderate to high degrees of astigmatism.
Presbyopia
In infancy and childhood the natural lens of the eye is soft and pliable and is easily altered in shape by the ciliary muscles of the eye through a process called accommodation.
Throughout life the lens of the eye gradually hardens, becomes less pliable, and progressively increases its resistance to change in shape. This leads to greater difficulty in focusing at near and, by the age of about 45 years of age, most people require reading correction, assuming their vision is corrected for distance. This condition is known as presbyopia.
Symptoms of Presbyopia
Most patients with presbyopia first notice difficulties while attempting to perform near distance tasks, such as reading. There may be blurring of near objects, or discomfort and fatigue with attempted near vision tasks.
Some presbyopic individuals complain that their vision remains blurred for a few moments (or even minutes) after looking up from sustained near vision tasks. This is due to the lag of relaxation of accommodation after excessive near focusing in the presbyopic age group.
Many patients complain that their "arms are too short", a statement that indicates accommodative powers are declining.
Correction of Presbyopia
Bifocal Glasses
Most patients in the presbyopic age range will opt for a pair of bifocal glasses, though many other options are present.
Bifocal glasses have the distance correction in the top of the lens and a near reading "add" power in the lower segment. This lower segment is the equivalent of a near magnifier, the power of which is related to both age and visual acuity.
Those individuals who require little or no correction for distance may desire only a pair of "reading glasses". These glasses will need to be removed for far vision tasks, of course.
Contact lens wearers may opt for either "monovision" or bifocal contact lenses. Monovision refers to the wearing of one contact lens for distance and the other for near tasks, though the imbalance may be disturbing to some people. Bifocal contact lenses are an option to correct presbyopia, however, fitting may sometimes be difficult and time-consuming.
It's extremely important to have regular eye exams for your entire family.
To make an appointment for an eye exam, call us today at (954) 961-2200.
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