Why is the sclera so tough?

The sclera, the white outer layer of the eye, is tough primarily due to its dense, fibrous connective tissue composition, which consists predominantly of collagen fibers. This structural strength provides protection for the inner components of the eye and maintains its shape. Additionally, the toughness of the sclera helps withstand intraocular pressure and resist deformation, ensuring that the eye can function properly under various conditions.