These are disorders caused by our eyes not being able to properly refract the light coming into our eyes.

The light coming into our eyes must be refracted by the optical system of the eye and focused in the visual center at the back of the eye.

If the rays coming into our eyes are refracted more than they should be by our eye's own optical system, the patient cannot see far and becomes MYOP.

If the rays coming to our eyes are refracted less than they should be by our eye's own optical system, the patient becomes HYPERMETROP. They experience problems both far and near.

If the lights coming to our eyes are refracted differently in different meridians of the eye, the light cannot be focused in the visual center and causes ASTIGMAT, also known as defocus disease. The patient has vision problems both near and far. Headaches, fatigue, reluctance to read and work closely occur.

All refractive errors (myopia, hyperopia, astigmatism) can be corrected with glasses, contact lenses or laser and other surgical methods.