The two structures most important in the eye's refractive ability are the iris and the pupil.

Question

Quizplus · Accepted Answer

The two structures most important in the eye's refractive ability are the cornea and the lens, not the iris and the pupil. The cornea accounts for about 2/3 of the eye's total focusing power, while the lens accounts for the remaining 1/3. The iris regulates the amount of light entering the eye through the pupil, but does not play a role in the eye's refractive ability.

The Two Structures Most Important in the Eye's Refractive Ability