Most important factor determining convergence of light rays on the retina is -
It has already been explained that most important refractive structure of the eye is cornea with a dioptric power of 44. The dioptric power of the cornea is dependent on two factors:-

i) Directly related to the refractive index of cornea,
ii) Inversely related to radius of curvature of cornea
Dioptric power of cornea = Refractive index of the cornea - Refractive index of air / Radius of curvature of the cornea
Physical state of vitreous
Diopter power of lens
Curvature of cornea
Length of eyeball