Most impoant factor determining convergence of light rays on retina is -
The cornea is the most imponat refractive surface of the eye with a refractive index of 1.376. The reason for msximum refraction lies in the fact that when light travel from one refractive medium to other. In eye, there are three such refracting interfaces:- i)Air, ii)Aqueous iii) lens Reference : Optics of human eye 4th edition page15-20
Length of eyeball
Dioptre power of lens
Refractive index of cornea
Physical state of vitreous
Optics and refraction