When you scratch your eye, which part is actually being scratched?

The correct answer is the cornea, which is the clear, protective outer layer of the eye. When you scratch your eye, it is the cornea that is directly impacted because it is the surface that experiences contact and irritation.

The cornea plays a crucial role in focusing light onto the retina, and it is sensitive, containing many nerve endings. This sensitivity is what makes scratching the eye particularly uncomfortable. While the pupil, iris, and lens are essential parts of the eye, they are situated deeper within the eye structure and are protected by the cornea. Therefore, when one feels a scratch, it is indeed the cornea that is responding to the stimulus, often leading to tearing and discomfort as a protective response.