Our ability to see depends on the way that your eyes bend (refract) light.
A refractive error occurs when they do not bend it perfectly, preventing the eye from focusing light correctly. Common refractive errors can be corrected with glasses and contact lenses temporarily but surgery improves them on a long term basis.
Anatomical features affect the ability of your eyes to refract light and focus properly.
Below are the factors that can cause refractive errors:
Eye Length: While it may not seem to you that the shape of your eye is too long or too short, either condition can affect your vision. You may have nearsightedness if it is too long or farsightedness if it is too short.
Curvature of the Cornea: The lens on the front of your eye needs to maintain an entirely spherical shape to refract a proper image. Refractions from irregular cornea shapes can produce astigmatism.
Curvature of the Lens: When the curve of the lens conforms to the shape of your cornea and the eye length, there is no refractive error. However, a lens that is too flat causes farsightedness, and a curve that is too steep may produce nearsightedness types of problems.
