Radius of curvature of anterior surface of cornea?

Ans. B. 7.8. (Ref. Guyton Physiology 11th/pg. 617)The Cornea# The outermost layer of the eye through which light passes.# No blood vessels.# convexity of a radius of about 8 mm# Refractive Index: 1.3# Posterior (back) Surface- Distance along axis from corneal pole: .55 mm# Anterior (front) Surface- Radius of curvature: 7.8 mmAdditional Educational points:Total refractive power = 59 diopters.Refractive indices of various structures of eye:The lens system of the eye is composed of four refractive interfaces:1) the inter- face between air and the anterior surface of the cornea,2) the interface between the posterior surface of the cornea and the aqueous humor,3) the interface between the aqueous humor and the anterior surface of the lens of the eye, and4) the interface between the posterior surface of the lens and the vitreous humor.The internal index of air is 1;the cornea, 1.38;the aqueous humor; 1.33;the crystalline lens, 1.40; andthe vitreous humor, 1.34.