Most important factor determining convergence of light rays on the retina is
Length of eyeball
Refractive index of cornea
Dioptre power of lens
Physical state of vitreous
refracting structures with their refractive indices given in parentheses-cornea (1.37), the aqueous humour (1.33), the crystalline lens (1.42), and the vitreous humour (1.33).
The total dioptric power of the eye is about +60 D out of which about +44 D is contributed by the cornea and +16 D by the crystalline lens.