What is a refractive error?
Light rays entering the eye should focus on the retina for the image to be sharp and in focus. The two elements in the eye that focus the rays are the cornea and lens.
- If the rays focus on the retina the eye is emmetropic
- If the rays focus before the retina the eye is myopic (nearsighted)
- If the rays focus behind the retina the eye is hypermetropic (farsighted)
- If the rays focus in different spots the eye has astigmatism
