Question

Where does the greatest degree of refraction of light occur in the eye ?

Answer 1

The degree of refraction at an interface between two media depends on the difference in refractive index of the media. The refractive indices of air, cornea, aqueous humor, and the lens are 1.009, 1.376, 1.336, and 1.413 respectively. We can therefore see that the greatest degree of refraction in the eye's optical system occurs at the cornea, because of the large difference in refractive index. In fact, approximately 48 D of the eye's optical power is contributed by refraction at the anterior surface of the cornea.