Eye Diseases Introduction Some eye problems are minor and fleeting. But some lead to a permanent loss of vision. There are many diseases that can affect the eyes. The symptoms of eye diseases vary widely, depending on the problem. Treatment may include medicine, surgery or other therapies. This reference summary explains eye diseases. It talks about common symptoms of eye diseases, types of eye diseases, diagnosis and treatment. The Eyes The eyes are sophisticated organs. They collect light and focus it on the back of the eye, allowing us to see. The cornea is the front, transparent part of the eye. It allows light to enter the eye. The rest of the eye is covered with an outer layer called the sclera. An extra layer called the conjunctiva covers the front part of the eye. Light hits the iris, which is the colored part of the eye. The opening in the middle of the iris is called the pupil. The iris controls the amount of light that enters the eye by changing the size of the pupil. As light passes through the pupil, it goes through a clear lens. Like the lens of a camera, the lens of the eye focuses light onto the back of the eye. The capsule holds the lens in place. 1
After passing through the lens and before reaching the back of the eye, light rays travel through a transparent substance called vitreous. The back of the eye is called the retina. The retina changes light signals into electrical signals. These electrical signals are sent through the optic nerve to the brain, which translates these signals into images we see. General Symptoms Symptoms of eye diseases can vary widely. The most common symptom of an eye disease is blurry vision. Other common symptoms of eye diseases are: Double vision. Frequent eye prescription changes. Headlights, lamps or sunlight seem too bright. Poor night vision. Some eye diseases may also cause: A halo seen around lights. Cloudy vision. Colors to seem faded. Eye redness. Swelling, itching or burning eyes. Tunnel vision. Eye diseases can cause other symptoms as well. If you notice any of these symptoms or other changes, talk to your health care provider. 2
Cataracts A cataract is a clouding of the eye s lens. Cataracts are a common eye condition in adults aged 65 or older. Cataracts normally develop slowly. A cataract can happen in one eye or both eyes. It cannot spread from one eye to the other. The lens of the eye is made of water and protein molecules. As we age, sometimes the molecules clump together. This can start to cloud areas of the lens, blocking some light from reaching the retina and reducing vision. Clouded areas on the lens of the eye cause cataracts. Cataracts are mostly associated with aging. But they can also happen after an eye injury. Diabetes and smoking can also make a person more likely to develop cataracts. A personal or family history of cataracts can also increase a person s risk. If your health care provider determines you have cataracts, the treatment depends on how blurred your vision is and the degree to which it affects your lifestyle. In mild cases of cataracts, eyeglasses may help temporarily. But cataract surgery is often needed. In most cases, the clouded lens is replaced with an intraocular lens, or IOL. This is an artificial, permanent lens that requires no care. Patients cannot feel or see the new lens. Glaucoma Glaucoma is a group of eye diseases that can damage the eye s optic nerve. It can lead to blindness if not treated. Glaucoma usually happens when the fluid pressure inside the eyes slowly rises, damaging the optic nerve. There are often no symptoms at first. Without treatment, people with glaucoma will slowly lose their peripheral vision, or side vision. They seem to be looking through a tunnel. Over time, straight-ahead vision may decrease until no vision remains. Glaucoma usually only affects people over 60 years old. Rarely, glaucoma may be present at birth. For unknown reasons, African-Americans over the age of 40 have a higher risk of getting glaucoma. 3
If any of the following conditions exist, there is a higher chance of getting glaucoma: A family history of glaucoma. Diabetes. Eye surgeries. Other eye problems. After being diagnosed, glaucoma may be treated a number of ways. Medicine is usually tried first. If medicine cannot control eye pressure sufficiently, surgery may be needed. Eye drops and pills are types of medicine used to treat glaucoma. Some medicines cause the eye to make less fluid. Others lower pressure by helping fluid drain from the eye. Laser surgery, also called trabeculoplasty, may be needed if medicines alone do not keep eye pressure down. Often, glaucoma medicines are still needed even after laser surgery. Non-laser eye surgery may also be needed. The purpose of this type of surgery is to make a new opening for the fluid to leave the eye. Conjunctivitis Conjunctivitis is a common eye condition. It causes inflammation of the conjunctiva. The conjunctiva is the thin layer that lines the inside of the eyelid and covers the white part of the eye. Conjunctivitis is often called "pink eye" or "red eye." This is because it can cause the white of the eye to take on a pink or red color. Conjunctivitis may be caused by: Allergies. Bacterial or viral infection. Contact lens products, eye drops or eye ointments. Substances that cause irritation. 4
Pink eye usually does not affect vision. But infectious pink eye is very contagious. It can easily spread from one person to another. The infection will clear in most cases without medical care. But bacterial pink eye needs treatment. Treatment often includes antibiotic eye drops or ointment. To prevent the spread of pink eye, you should: Avoid touching your eyes with your hands. Avoid sharing eye cosmetics or personal eye care items. Avoid sharing towels or washcloths. Throw away your eye cosmetics. Wash your hands often. Retinal Disorders The retina is a layer of tissue in the back of your eye that senses light and sends images to your brain. In the center of this nerve tissue is the macula. The macula provides the sharp, central vision needed for reading, driving and seeing fine detail. Retinal disorders affect this vital tissue. Retinal disorders can affect your vision. Some can be serious enough to cause blindness. Common retinal disorders include: Macular degeneration. Diabetic eye disease. Retinal detachment. Macular pucker. Macular hole. Age-related macular degeneration, or AMD, is a disease that affects central vision. It is the leading cause of severe vision loss in people 60 and older. People rarely go blind from AMD. But AMD can make it difficult to perform daily activities. Diabetic eye disease is also called diabetic retinopathy. It happens when high blood sugar levels caused by diabetes damage the eyes. Diabetic retinopathy damages the tiny blood vessels inside your retina, affecting vision. 5
A retinal detachment lifts or pulls the retina from its normal position. It can happen at any age, but it is more common in people over age 40. A retinal detachment is a medical emergency. If not promptly treated, it can cause permanent vision loss. Macular pucker is scar tissue on the macula. It can cause blurred and distorted central vision. Macular hole is a small break in the macula that usually happens to people over 60 years old. Treatment for retinal disorders depends on the cause. Some mild retinal disorders do not require treatment. When retinal disorders affect vision or daily activities, surgery may be needed. Summary Some eye problems are minor and fleeting. But some lead to a permanent loss of vision. There are many diseases that can affect the eyes. Common eye problems include: Cataracts. Glaucoma. Conjunctivitis, or pink eye. Retinal disorders. The symptoms of eye diseases vary widely, depending on the problem. The most common symptom of an eye disease is blurry vision. Other common symptoms of eye diseases are: Double vision. Frequent eye prescription changes. Headlights, lamps or sunlight seem too bright. Poor night vision. Treatment for eye diseases may include medicine, surgery or other therapies. Talk to your health care provider if you think you may have an eye disease. In most cases, treatment can help improve vision and prevent blindness. 6