The lecture has been given on Feb. 14th, 2011 by Dr. Tara.

2. Fig. The eye. C, the cornea. B, in the anterior chamber, filled with aqueous. L, the lens. H, in the vitreous. M, the macula. 0, the optic nerve. FA, the optic axis, meeting the retina at A.. N, the nodal point.

4. Fig. The reduced eye. The upper figure represents the normal eye, with the two focal points at F and F' , the two principal points at E and E' and the two nodal points N and N' . The reduced eye, drawn in scale to correspond, with the two principal foci at F and F' , the single refracting surface corresponding to the mean of E and E' , and the nodal point at N , corresponding to the mean of N and N‘ .

5. Fig. The formation of retinal images . The image ab of an object AB is formed by drawing lines from A and B through the nodal point N. cd is the position of the refracting surface of the reduced eye. ANB or aNb represents the visual angle.

28. Convex lenses in the form of reading glasses therefore are needed to converge the light rays from close objects. This occurs earlier in hypermetropes than myopes. The physical part is related to hardening or sclerosis of the crystalline lens that reduces the elasticity of the lens capsule and the plasticity of the lens core. The physiologic part of accommodation is the innervation and contraction of the ciliary muscles. Some hold that sclerosis of the ciliary body reduces its ability to constrict, and the lens does not sufficiently obtain the conditions required for changing its shape

31. Thank you