By Kapil G. Kapoor, MD
Maintaining vision for geriatric patients is a component of their very basic health. As a retinal provider, I admit to ample bias in suggesting that visual health is truly integral; in spite of my confessed partiality, the data does in fact support this! Aging patients with severe vision loss have significantly increased risk of falls and fractures, increasing the likelihood of hospital or nursing home admissions and/or disability. Basic activities critical to daily health can become challenging with even moderate visual impairment, including identifying medications, bathing, dressing, or safely navigating familiar areas like the home or the grocery store. It’s easy to see why there is significant increase in depression associated with visual impairment with aging.
Of the vision problems that beset older patients, age-related macular degeneration (AMD) is by far the most prevalent, and the greatest threat to these patients. AMD affects more than 10 million people in the US, and as our population ages, that number is expected to increase significantly. Establishing a basic familiarity with this condition will enable all of us to protect our patients.
AMD deteriorates the macula, which is responsible for central vision and focusing on fine detail. Visual decline corresponds to the stages of dry AMD that often progress slowly, but can convert unpredictably to the potentially more devastating wet AMD.
In early dry AMD, characterized by small drusen (small yellow deposits made of lipids), patients may experience slight blurry vision centrally, or metamorphopsia (noticing small wavy lines when trying to focus on a straight line.) In intermediate dry AMD, these symptoms become more pronounced, with many patients experiencing fatigue when reading, often closing one eye due to a slight asymmetry of disease. In advanced AMD, patients develop atrophy, typically where drusen developed. Histologically, this corresponds to cell death, and functionally translates to gaps in vision. In the earliest stages of atrophy, patients experience loss of contrast, increased glare, and often describe skipping letters when reading. In the most advanced stage, atrophy becomes confluent throughout the central macula and patients can become legally blind.
The typical progression through the stages of dry AMD is slow, occurring over several years to decades. However, approximately 10-15 percent of patients with dry AMD can convert to the wet form of AMD, where a new vessel forms right in the center of vision, potentially leading to severe vision loss over weeks or even overnight. Our best understanding supports that chronic oxidative stress in this aging macula creates a feedback demand for more oxygen, which engenders this harmful vessel to recruit more oxygen. Rather than actually recruiting any oxygen, this new vessel just bleeds and starts making a blind spot in the central visual field. Fortunately, we have developed treatments in the form of intravitrael injections of anti-VEGF for the wet form of macular degeneration. These treatments play superb defense – with over 95 percent of patients avoiding further severe vision loss after timely treatment. These treatments also play better and better offense, with approximately half of patients enjoying a significant improvement in vision after converting to the wet form of AMD.
Kapil G. Kapoor, MD is a Board certified ophthalmologist specializing in vitreoretinal surgery. wagnerretina.com
