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Vision loss, symptoms and precautions
By Andrew Danyluk, M.D.
The eye is very complex and with age complicated vision problems often develop. Some problems may be reversed with medical care, but it is vital to understand the symptoms presaging a loss of vision so that timely ophthalmic intervention may prevent permanent problems.
One problem is macular degeneration, where the fine central vision of the eye is lost as a result of damage to the retina. The loss can be gradual, where the central light-sensitive retinal cells die, or it can be abrupt, as when blood and fluid leak into the retina, disrupting its architecture. The primary symptom of macular degeneration is a central loss of vision. For example, when staring at a door edge, the center of the door may be distorted or blurred out. Timely evaluation by an ophthalmologist and treatment, especially if the leaky form of macular degeneration is present, can, in some cases, improve the vision. Although the fundamental cause for macular degeneration is unknown, risk factors include exposure to unprotected sunlight, smoking, and atherosclerosis. Eating green leafy vegetables and taking high dose antioxidant vitamins can decrease the risk of losing vision in patients with macular degeneration.
Glaucoma is a condition where the pressure inside the eye causes damage to the nerve of the eye. The nerve connects the eye to the brain, therefore damage results in a loss of vision. The vision lost is the side vision, which is why the loss is not noticed until much damage has occurred. Once damage has occurred through glaucoma, the only treatment is to lower the eye pressure to prevent any further damage. Risk factors for glaucoma are a family history of glaucoma, elevated ocular pressures, and optic nerves that are susceptible to damage. Routine ophthalmic examination is crucial in preventing loss of vision from glaucoma. There is an infrequent type of acute or sudden glaucoma, which occurs most often in farsighted individuals and those of Asian ancestry. Untreated, acute glaucoma can cause a total loss of vision within hours of having symptoms. Patients with acute glaucoma experience sudden, severe eye pain with haloes around lights, severe eye redness, and nausea. Routine eye examinations can identify individuals at risk for acute glaucoma and a laser treatment can prevent its development.
Retinal detachment is when the thin light-sensing layer of the back of the eye separates from its nourishing foundation, thereby causing the light-sensing part to die and result in a loss of function. If surgically reattached within a week, most people regain 90% of their vision. However, the longer the retina is detached, the less vision will be restored. Risk factors for retinal detachment are high levels of nearsightedness, retinal thinning, diabetes, and engaging in activities where the head can be violently shaken, such as boxing. Symptoms of retinal detachment start with flashing lights and fl oaters, and eventually include a curtain or shadow, blocking vision out of one eye.
Circulatory damage to the retina causes permanent loss of vision, because the retina loses its source of oxygen and the resulting fluid leakage causes retinal swelling, distorting, and eventually damaging the retinal architecture. There are two types of causes underlying circulatory problems. The most common cause is narrowing of blood vessels from atherosclerosis. Risk factors for atherosclerosis include elevated cholesterol and/or blood pressure, high triglycerides, diabetes, and smoking. Atherosclerotic circulatory problems in the retina cause a sudden painless loss of vision.
In addition to controlling the atherosclerotic risk factors, use of laser treatment and medications to decrease the retinal swelling and leakage can stabilize vision. The second, more unusual form, of retinal circulatory damage is called temporal arteritis. In this condition, inflammation occurs in the wall of the blood vessels causing blockage, resulting in a stroke. Patients that develop this condition are typically over 60 and usually have severe pain in their temples to the point where the skin is sensitive to the touch. In addition, they may experience pain while chewing food, weakness and soreness in their jaw muscles, as well as unexplained fevers. Vision may be lost in only a few hours, making timely evaluation crucial as prompt treatment with prednisone may prevent loss of vision.
Establishing a relationship with an ophthalmologist and requesting timely consultation when symptoms occur, are critical to preventing and treating conditions that may cause a loss of vision.
Dr. Andrew Danyluk is board certified in both Ophthalmology and Internal Medicine. He is an Associate Professor of Ophthalmology and Medicine at the University of Massachusetts. His office is in the Medical Arts Complex at Berkshire Medical Center and he can be reached at 499-6405.