We’ve all heard the term “cataract,” but what is it, exactly? In honor of Cataract Awareness Month, we’re going to try to provide answers to the most common questions and concerns regarding this common condition, especially in seniors.
Cataracts affect our eyesight much the same way as a dirty windshield: some types of cataracts cloud the whole lens equally, and other types only obscure very specific areas.
In describing cataracts to patients, I compare them to a dirty windshield in a car. The windshield may be dirty and obscured over the entire surface, or there may be various areas that are perfectly clear and others that are dirty. There may even be “stars” in the glass due to rock chips. The location of windshield dirt governs how much it affects a driver’s vision. If a large area of dirt is only over the passenger side of the windshield, the dirt is not likely to hinder the driver much. However, if the entire windshield is clean with the exception of a small area right in front of the driver’s line of sight, the small area of dirt may significantly impede the driver’s ability to see well.
Nuclear, cortical, and posterior sub-capsular cataracts are the three most common types of cataracts. Though the manner in which each type of cataract affects vision is slightly different, their treatment is the same. Entire textbooks have been written to exhaustively cover the various types of cataracts that exist, but the fundamental problem of any cataract is that it interferes with the clear transmission of light to the retina.
Symptoms of Cataracts
The symptoms vary according to the type of cataract but commonly include complaints of cloudiness to the vision as well as an overall reduction of the best corrected vision. Additionally, increased glare is among the top complaints caused by cataracts. Glare is typically most bothersome at night, especially while driving. The cataract opacities in the lens act to scatter light entering the eyes, inducing glare. The glare and scattered light may be so pronounced that they cause double vision. Cataracts often cause colors to lose their vibrancy, and people complain that colors become “washed out.” The color vision changes are gradual, so they may not be perceived until the cataract is removed, upon which color vision quickly restores to normal.
Risk Factors for Cataracts
Just as dermatologists remind us to protect our skin from the sun’s ultraviolet (UV) light by using sunscreen, protecting the eyes from UV light is just as important. Ultraviolet light is believed to be the primary cause of cataracts for most people. UV light exposure is received when we are in sunlight, so we need to limit our UV exposure.
Other risk factors for cataracts include diabetes, smoking, trauma to the eye, electrocution, and prolonged steroid use. Steroids such as prednisone are commonly prescribed to treat a host of conditions, including arthritis, asthma, and other autoimmune diseases. Using steroids for a few days or weeks poses little increased risk, but long-term usage at higher doses is strongly linked to cataract formation. Cataracts may also form as a result of ocular trauma. Traumatic cataracts may not develop until long after the initial injury; people with a history of “black eyes,” sports injuries, or car accident victims with head trauma sometimes develop cataracts months or years later.
Early stages of cataracts are managed without surgery. Updating eyeglass lenses to keep pace with the changes induced by cataracts is critical. It is not unusual to need eyeglass prescription updates more frequently in the early stages of cataract development. Non-glare lens treatments for the eyeglass lenses help reduce (but do not eliminate) glare caused by the cataracts. One of the best ways of optimizing vision with cataracts is to use prescription polarized sunglasses while outside and when driving. Polarized lenses filter out light rays that contribute to glare, and they effectively counteract glare caused by cataracts by reducing the light scatter.