Introduction
Refractive errors are eye disorders that occur when the curvature of the eye inhibits light from focusing directly at the back. This usually results in blurred visions.
Normally, light refracts as it passes through the lens and the cornea and then focuses directly on the retina. However, with varying eye shapes in individuals, light may not be focused correctly. When this happens, one is said to have a refractive error.
In myopia, the light is focused in front of the retina instead of on it. Therefore, only close objects can be seen clearly while distant images appear blurred.
In hyperopic persons, the light is directed behind the retina. This causes distant objects to appear clearer than close-up objects.
Astigmatism arises from an asymmetrical curvature of the lens or cornea. As a result of the irregular shape, light is unevenly focused on the retina. Individuals with astigmatism experience blurry vision at a certain distance.
After years of proper vision, presbyopia may also develop. This condition causes loss of near vision with age. It occurs after around 40 years when the natural lens of the eye hardens up and cannot easily flex to direct focus on nearby images.
Sub-Types
- Myopia (nearsightedness)
- Hyperopia (farsightedness)
- Astigmatism
- Presbyopia
Signs & Symptoms
- Blurred vision
- Straining of the eyes
- Haziness
- Headaches
- Squinting of the eyes
- Halos around bright lights
