Refractive

Refractive error is a common eye disorder where the eyes are unable to clearly focus on images. This can result in blurred vision. The main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia.

Causes

Refractive errors occur when the shape of the eye prevents light from focusing directly on the retina. This can be due to the length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens.

Types

Myopia

In myopia, the eyeball is too long or the cornea is too curved. As a result, light rays focus in front of the retina, causing distant objects to appear blurry.

Hyperopia

In hyperopia, the eyeball is too short or the cornea is not curved enough. This causes light rays to focus behind the retina, making close objects appear blurry.

Astigmatism

Astigmatism is caused by an irregularly shaped cornea or lens. This causes light to focus on more than one point on the retina, resulting in blurry or distorted vision at all distances.

Presbyopia

Presbyopia is an age-related condition where the lens becomes hard and less flexible. This makes it difficult to focus on close objects.

Diagnosis

Refractive errors are diagnosed through a comprehensive eye examination. This includes a visual acuity test, a refraction test, and an examination of the health of the eyes.

Treatment

Treatment for refractive errors may include eyeglasses, contact lenses, or refractive surgery. The choice of treatment depends on the type and severity of the refractive error, as well as the patient's lifestyle and occupation.

See also

• Eye examination
• Visual acuity
• Refractive surgery

Refractive Resources
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