Your cornea is the clear front part of your eye. It is like a window that controls and focuses the light coming into the eye. If your cornea has an irregular shape, the light does not focus properly. Everything looks blurry. This is a refractive error.

Four common refractive errors are

• Myopia, or nearsightedness - clear vision close up but blurry in the distance
• Hyperopia, or farsightedness - clear vision in the distance but blurry close up
• Presbyopia - inability to focus close up as a result of aging
• Astigmatism - focus problems caused by the cornea

Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility.