272 Introduction to Anatomy & Physiology Macular Degeneration The hallmark symptom of macular (MAK- yoo-lar) degeneration is a progressive loss of central vision. This disorder occurs in about 10 percent of elderly people. Peripheral vision, however, remains unaffected. There are two types of macular degeneration: dry and wet. Dry macular degeneration is caused by progressive thinning of the retina. Although no treatment currently exists, most individuals with this condition do not completely lose their eyesight and are able to function with vision aids. Wet macular degeneration involves leakage of small blood vessels within the eye. Some individuals with this condition respond favorably to medication or laser surgery (Figure 7.10). Glaucoma Glaucoma (glaw-KOH-ma) is a condition of increased pressure within the eyeball caused either by overproduction of aqueous humor or blockage of normal aqueous humor drainage. The onset of symptoms is gradual and includes aching eyes, poor vision in dim light progressing to blurred vision, and the appearance of halos around lights. As the condition progresses, tunnel vision—or loss of peripheral vision—occurs, and blindness eventually follows. Untreated glaucoma is a common cause of blindness. Glaucoma occurs in about 20 percent of adults older than 40 years of age. Early detection is a must! Glaucoma can be readily treated with medication or surgery. Common Eye Diseases and Disorders Etiology Prevention Pathology Diagnosis Treatment Conjunctivitis infection, causing inflammation of the conjunctiva avoid contact with infected people redness, pain, swelling, mucous discharge of the eyes physical exam, questions regarding symptoms wet compresses, artificial tears antibiotics if caused by bacteria Cataracts progressive clouding of the lens of the eye avoid bright sunlight blurred vision, poor night vision, yellowing of colors, seeing halos around lights vision tests surgery to replace the lens with an artificial lens Glaucoma increased pressure within the eyeball due to buildup of aqueous humor none aching eyes, poor vision in dim light progressing to blurred vision, seeing halos around lights specialized tests prescription eyedrops, oral medications, laser treatment, surgery Dry and wet macular degeneration dry: progressive thinning of the retina wet: leakage of capillaries within the eye none progressive loss of central vision specialized tests dry: none wet: medications to hinder growth of new blood vessels Diabetic retinopathy long term diabetes causes swelling and leaking of the vessels that supply blood to the retina health habits to prevent type 2 diabetes bleeding within the eye causes seeing red spots eye examination varies, depending on type and severity of condition Vitreous floaters bits of vitreous humor break off and float in the aqueous humor in the center of the eyeball none drifting specks in visual field if combined with flashes of light on lateral periphery may indicate retinal injury eye examination none laser surgery to correct retinal injury if warranted Figure 7.9 Goodheart-Willcox Publisher Copyright Goodheart-Willcox Co., Inc.