In addition to the various disorders involving only the eye, there are number of generalized diseases that affect vision. Among thses are arteriosclerosis, diabetes mellitus, and hypertension or high blood pressure, which often cause abnormalities in the bloodvessels of various parts of the eye. These abnormalities can lead to tissue changes that cause the patient to se spots or to notice that his vision is defective. Diease of the brain, such as multiple sclerosis, tumrs, and abscesses, although rare, can result in double vision or loss of lateral or central vision. Any sudden or gradual changes in vision should be brought to a physician’s attention promptly, since early diagnosis and treatment is usually effective and can prevent serious deterioration.