REFRACTIVE ERRORS/VISION PROBLEMS
The most common vision problems are caused by refractive errors – which means that the shape of your eye does not bend light correctly, resulting in a blurred image. Refractive disorders are usually the result of an eyeball that is too short or too long, a cornea (the clear front part of your eye) that is irregularly shaped, or a lens that is curved too much or too little. The main types of refractive errors are myopia (nearsightedness), hyperopia /(farsightedness), presbyopia (loss of near vision with age), and astigmatism.
Myopia (close objects are clear, and distant objects are blurry) – Also known as nearsightedness, myopia is usually inherited and often discovered in childhood. Myopia often progresses throughout the teenage years when the body is growing rapidly.
Hyperopia (close objects are more blurry than distant objects) – Also known as farsightedness, hyperopia can also be inherited. Children often have hyperopia, which may lessen in adulthood. In mild hyperopia, distance vision is clear while near vision is blurry. In more advanced hyperopia, vision can be blurred at all distances.
Presbyopia (aging of the lens in the eye) – After age 40, the lens of the eye becomes more rigid and does not flex as easily. As a result, the eye loses its focusing ability and it becomes more difficult to read at close range. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism.
Astigmatism – Astigmatism usually occurs when the front surface of the eye, the cornea, has an asymmetric curvature. Normally the cornea is smooth and equally curved in all directions, and light entering the cornea is focused equally on all planes, or in all directions. In astigmatism, the front surface of the cornea is curved more in one direction than in another. This abnormality may result in vision that is much like looking into a distorted, wavy mirror. Usually, astigmatism causes blurred vision at all distances.
A refractive error is usually diagnosed during a routine eye examination. Testing usually consists of asking the patient to read a vision chart while testing an assortment of lenses to maximize a patient’s vision. Special imaging or other testing is rarely necessary, but Dr Boitumelo Khantsi is able to provide all the tests necessary to accurately diagnose any refractive errors you may have.