For a normal eye, the cornea provides a converging power of 35 D and the least converging power of t

Question

For a normal eye, the cornea provides a converging power of 35 D and the least converging power of the eye lens behind the cornea is 15 D. Using this information, the estimated distance between the retina and the cornea-eye lens system is

Professor PC Thomas Classes · Answer

(b) : The total converging power of the eye system is the sum of the power of the cornea and the eye lens. $P_{total} = P_c + P_e = 35 	ext{ D} + 15 	ext{ D} = 50 	ext{ D}$. The focal length of the eye system is $f = 1 / P_{total} = 1 / 50$ m. Converting this to centimeters, $f = 100 / 50$ cm $= 2.0$ cm. The distance between the lens system and the retina is equal to this focal length, which is 2.0 cm.