In which part of the eye does the majority of light refraction occur?

The majority of light refraction occurs in the cornea due to its curvature and transparency. The cornea is the eye's outermost layer and plays a crucial role in focusing light onto the retina. Its refractive power is about 43 diopters, which accounts for approximately two-thirds of the total refractive power of the eye.

While the lens also contributes to refraction, its primary function is to fine-tune the focus of light by changing shape, allowing for accommodation when focusing on objects at various distances. The iris, which controls the amount of light entering the eye by adjusting the size of the pupil, does not contribute to refraction. The retina is responsible for converting light into neural signals, but it does not play a role in refracting light itself. Thus, the cornea is indeed the part of the eye where the majority of light refraction occurs.