As we age, certain ocular conditions become more common, including presbyopia (the need for reading glasses), floaters (degenerative changes in the vitreous gel), cataracts,
glaucoma, and macular degeneration. Often these disorders cause a change in vision but
some may be asymptomatic; therefore, it is important to have routine eye exams after age
40 years old, particularly if you have a family history of glaucoma or maculardegeneration.
Cataract
A cataract is a clouding of the lens inside the eye. The lens is clear when we are young, but becomes discolored and opaque as we grow old. Cataracts can occur at any age but typically do not significantly affect vision until our senior years. Other causes of cataracts include eye diseases (particularly inflammation inside the eye), systemic diseases (diabetes), trauma, medications (steroids), and environmental exposures.
The most common symptom is blurry vision. Initially, new glasses may help because cataracts can change the focusing power of the eye. People with cataracts may also notice difficulty seeing in low light conditions and colors may appear faded. This is due to decreased contrast sensitivity, similar to wearing sunglasses indoors. Cataracts can also cause glare or starbursts from bright lights, and in rare cases, double vision in one eye.
Cataracts typically grow slowly causing a gradual deterioration in vision, but once the central portion of the lens is affected a sudden change in vision may be noticed. The treatment for cataracts is surgery to replace the cloudy lens with a clear lens implant. Cataract surgery is performed when you decide you require better vision. It is performed as an outpatient procedure under local anesthesia, and visual recovery is rapid. Advances in technology have made the operation safer and highly successful.
Glaucoma
Glaucoma refers to optic nerve damage most commonly due to high eye pressure and is a leading cause of blindness. This is unfortunate because loss of vision from glaucoma can be prevented with early detection and treatment.
In primary open angle glaucoma, the most common form, a gradual, painless loss of peripheral vision occurs until the late stages when the nerve is severely damaged and central vision is affected. Glaucoma increases is most common after age 60 years old,
but it can occur in younger adults and children. Beside elevated eye pressure, other risk factors are family history, race (African American), and possibly hypertension, diabetes, cardiovascular disease, and nearsightedness. Because it is asymptomatic until the late stages, glaucoma can cause substantial visual loss. Therefore, it is important to have regular screening exams to measure eye pressure and examine the optic nerves. Peripheral visual field testing may also be performed. If glaucoma is detected, treatment can prevent further nerve damage and blindness. Options include eye drops, laser procedures, and surgery.
Acute angle-closure glaucoma is a rare form of the disease in which the pressure rapidly increases (in predisposed eyes) causing acute pain, blurred vision, headache, nausea, and colored halos around lights. This is a medical emergency requiring immediate treatment.
Macular Degeneration
Age-related macular degeneration (AMD) is characterized by damage to the center of the retina (macula), which causes central vision loss. Peripheral vision is not affected.
In addition to increasing age (>75 years old), other risk factors include family history, gender (female), race (Caucasian), smoking, hypertension, hypercholesterolemia, cardiovascular disease, light iris color, and farsightedness. There are two types of AMD: 1) the dry or nonexudative form (more common) causing atrophy of the macula and resulting in gradual loss of vision, and 2) the wet, exudative, or neovascular form (less common) causing abnormal blood vessel growth under the macula. These new vessels can leak fluid or blood producing a sudden, often profound loss of vision.
The visual loss ranges from mild to severe, and each eye can be affected differently. Initially the central vision becomes distorted and blurry. Straight lines may look bent or wavy, and small blind spots may appear. Eventually the central vision may be completely dark or missing.
A retinal examination is necessary to diagnose macular degeneration, and the disease can often be detected before vision is affected. Once macular degeneration is diagnosed, observation with periodic eye exams and self-monitoring by looking at a grid pattern (Amsler grid) are recommended. Nutritional supplements (AREDS2 vitamins) may be beneficial for individuals who already have mild degrees of dry AMD. Low vision devices such as magnifiers, special computers, and large-print books, aid in daily activities and help improve visual function.
Treatment exists for wet AMD as well as severe dry AMD (known as geographic atrophy). Therefore, any sudden change in central vision warrants prompt evaluation. Special imaging techniques help identify the presence of neovascularization, which can be treated with intravitreal medications. AMD cannot be cured, but treatment often improves acute visual loss in the wet form and slows the rate of disease progression.
Niel Friedman, MD, November, 2024
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