The term "sclera" refers to the tough, fibrous, and white outer covering of the eye. It forms the protective, continuous layer that envelops the eyeball, except for the frontal portion covered by the transparent cornea. The sclera is composed primarily of collagen fibers that lend it strength and resilience.
The main function of the sclera is to provide structural support and protection to the delicate internal structures of the eye, such as the retina, optic nerve, and choroid. Its sturdy composition allows it to maintain the shape and integrity of the eyeball, preventing it from collapsing under external pressure.
In addition to its protective role, the sclera also plays a crucial role in eye movement. The extraocular muscles, responsible for moving the eye in various directions, attach to the sclera, allowing for coordinated and precise movements.
Although the sclera is commonly referred to as white, it may exhibit some variations in color, ranging from off-white to bluish or yellowish tints. This color variability may be influenced by factors such as age, genetics, and certain medical conditions.
In summary, the sclera is a dense, fibrous covering that encloses and safeguards the eye. Its primary functions include providing structural support, protecting internal structures, and facilitating eye movements.
