<prompt> 1mm change in the axial length of the eyeball produces a change in refractive index by: March 20051 D2 D3 D4 D  <response>: Ans. C: 3D 1mm change in the axial length of the eyeball produces a change in refractive index by 3 D. Elongation produces myopia and shoening causes hypermetropia. 1 mm change in the radius of curvature of the cornea produces a 6 D refractive change. Steeper more curved corneas produce myopia and flatter corneas hypermetropia. 