Blue discoloration of the whites of the eyes is rare and occurs when there is abnormal thinning of the sclera, which is the white outer wall of the eye. Most cases of such blue discoloration occur in young children with rare severe congenital abnormalities of the musculoskeletal system. Some patients with Marfan's syndrome, a congenital condition that may not become apparent until teenage years or later, may show a bluish discoloration of the whites of the eyes. In older individuals, there may be bluish or grayish areas of thinning of the sclera near the inner or outer corners of the eyes where some of the muscles that move the eye are attached to the white of the eye; such thinning is benign and requires no treatment.
Eye discoloration can sometimes be a symptom of certain diseases and medical conditions. Primary acquired melanosis, for example, is a medical condition that most often affects middle-age or elderly caucasians, resulting in a brown patchy appearance to the sclera of the eye. While primary acquired melanosis does not generally affect the health or functioning of the eye, it must be monitored. According to researchers at the University of Utah John A. Moran Eye Center, certain forms of primary acquired melanosis can progress to melanoma, a very deadly form of skin cancer. Other diseases and medical conditions that can cause eye discoloration include Addison's disease, macular degeneration, and pigmentary glaucoma.