In this situation, leaving the injured eye in place for more than 12 days precipitates the loss of vision in the uninjured eye, resulting eventually in total blindness. Luckily, the tragedy is rare and becoming rarer, occurring in only 0.1 percent of cases, down from 2 to 4 percent during the early part of the 20th century. In more severe cases, the damage penetrates the cornea, making it opaque and white. When this occurs, the injury is usually irreversible. Corneal transplants are necessary to restore sight, and even this measure is not always successful in restoring the severely burned eye.
Subconjunctival hemorrhages appear as sudden red blobs in the white of the eye.
They usually form after a small injury to the eye, or sometimes as the result of a cough or a sneeze. Although these blobs look alarming, they are almost always harmless. Recurrences, however, may indicate a blood disease or high blood pressure. While most are harmless, brown or red spots are often signs of vitreous hemorrhage, leakage of blood from the retina into the vitreous chamber. These spots are danger signs and may be followed by retinal detachment, a process that often begins with a shower of sparkling spots and the sensation of a curtain moving across the eyes.