What is the main role of the sclera?

The sclera serves primarily as a protective outer layer of the eye and is crucial in maintaining its shape. This tough, white part of the eye provides structural support, ensuring that the eye retains its globe-like form, which is essential for proper functioning. By maintaining the shape, the sclera helps to sustain the positioning of other internal components of the eye, such as the lens and the retina, which need to be aligned correctly for optimal vision.

While the other options relate to important functions of the eye, they do not accurately describe the primary role of the sclera. Light refraction is mainly carried out by the cornea and the lens, tears are produced by the lacrimal glands, and focusing light onto the retina is primarily a function of the lens. The sclera's role as a supportive and protective structure is fundamental to the overall integrity and functionality of the eye.