Which of the following does NOT contribute to refraction in the eye?

Refraction in the eye is primarily the bending of light as it passes through various optical components, allowing for focusing on the retina. The cornea and lens are the major structures responsible for this refraction.

The cornea has a fixed curvature and provides the majority of the eye's total refractive power. The lens, with its adjustable shape, fine-tunes focus for near and distant objects. The aqueous humor, the clear fluid in the anterior chamber of the eye, also plays a role in refraction, but it is more about maintaining eye pressure and providing nutrients than direct light bending.

In contrast, the macula, which is a small area on the retina responsible for central vision, does not participate in the refraction of light. It is involved in the processing of visual information but does not contribute to the optical power needed to refract light. Therefore, the macula serves as a crucial area for sharp vision but is not an optical component that focuses light, making it the correct choice for this question.