Healthy vision is dependent on your lens and cornea. Problems like refractive errors are caused by a cornea that is not shaped perfectly. The cornea happens to be the clearer part on the surface of the eye. The job of the cornea is to bend and focus the light waves. With refractive errors, the light that is coming from an object focuses on the retina. This results in a blurred image. Refractive errors can occur in healthy eyes as well said Dr Ritika Sachdev, Additional Director, Centre for Sight.

What are the types of refractive errors?

Nearsightedness (Myopia) –

It is usually inherited and it can be discovered during one’s childhood itself. This disorder progresses across one’s teenage years when the body is still developing. People who have a higher magnitude of myopia tend to have a major risk of retinal detachment (this may require surgical repair).

Farsightedness (Hyperopia) –

This kind of refractive error can also be inherited. Children who develop hyperopia may lessen it in their adulthood. In the case of mild hyperopia, the distance vision is better whereas near vision is blurred. In the case of advanced hyperopia, vision may get blurred at varied distances.

Astigmatism –

It occurs when the cornea has an asymmetric curvature. Usually, the cornea is equally curved in all directions. The light when it enters the cornea is focused equally in all directions. But in astigmatism, the cornea’s front surface is curved more in one particular direction than another. This kind of abnormality may affect the vision that is similar to looking at a distorted or wavy mirror. In general, astigmatism causes blurred vision at various distances.

Presbyopia –

After the age of 40, the lens tends to become rigid and it does not flex easily. Thus, the eye loses its focusing ability and the person is not able to read at a closer distance. This usual phenomena of aging of the lens can be associated with astigmatism, myopia, or hyperopia as well.

What is refractive surgery?

Refractive eye surgery helps improve the affected eye’s refractive state. It reduces or totally eliminates the dependency on glasses or contact lenses. There are different methodologies to correct errors like the surgical remodeling of the cornea (keratomileusis), lens replacement or lens implantation (cataract surgery).

About the author- Dr Ritika Sachdev , Additional Director , Centre for Sight