12. The Optical System of the Eye The divergent light rays must pass through an optical system that brings them back into focus. The cornea & lens is the optical system of the eye that focus light rays onto the retina
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22. The lens becomes more spherical during near vision (contraction of ciliary muscle)
32. Cylindrical lens in suitable plane Contact lens. Biconvex lens ( ↑ refractive power) Biconcave lens (diverge) ttt - Unequal curvature of cornea or lens. -short eye ball - Weak lens -long eye ball -Strong lens Cause Focus of rays in one plane is at different distance from that of rays in another plane. Focus behind retina Focus in front of retina Defect Astigmatism Hypermetropia Myopia