Question

Calculate the focusing power of the lens in the fish eye. Assume that the lens is spherical
with a diameter of 2 mm. The index of refraction for water is 1.33, the lens index of refraction 1.4,
and vitreous humor and aqueous humor have similar refrection index 1.34.

Answer 1

$D = 2 \;mm$

$R = \frac{D}{2} = 1 \;mm = 0.1 \;cm$

$M_{lens} = 1.4$

$M_{ah} = 1.34$

$R_1 = +R$

$R_2=-R$

$\frac{1}{f} = (\frac{M_{lens}}{M_{ah}} -1)(\frac{1}{R_1} – \frac{1}{R_2})$

$\frac{1}{f} = (\frac{1.4}{1.34} – 1)(\frac{2}{R})$

$P = \frac{1}{f} = 0.0447\times20=0.894 \;Dioptre$

Answer: 0.894 Dioptre