Refractive index of cornea is: September 2007

Ans. B: 1.38Looked at from the front the cornea is about 12 mm horizontally and 11 mm veically.It is the first and most impoant refracting surface of the eye, having a power of about 43 D.The anterior surface has a radius of curvature of about 7.8 m, the posterior surface 6.5 mm, and the central thickness is about 0.5 mm.Cornea is comprised of several layers and, therefore, the optical propeies are measured for the whole cornea rather than generalizing from a tissue sample.