How Macular Degeneration Affects Vision
A progressive eye disease, age-related macular degeneration (AMD) may occur in one or both eyes and may advance very slowly or quite rapidly. While the condition can be devastating, ophthalmologists reassure patients that macular degeneration alone will not lead to total blindness. The reason is that both the dry and the wet forms of macular degeneration affect the central part of vision but peripheral, or side vision, is preserved.
As a vision rehabilitation specialist, I help people who have visual impairments better understand their eye conditions. Frequently, my clients are confused by what they can or cannot see. Family members may be mystified by the fact that 75-year-old Aunt Millie needs a magnifying glass to read a menu, yet she can navigate a crowded restaurant with ease and even spot a dropped spoon on the floor.
Millie has the dry form of AMD, the most common cause of age-related vision loss. Cells in the central part of her vision called the macula have deteriorated, so Millie struggles to do things that require very sharp vision, such as reading, playing cards, or chopping vegetables. But Millie often surprises herself when she can see things out of the corner of her eye. Millie’s visual functioning varies depending on the task she is doing and whether she is using her damaged central vision or relying on intact peripheral vision.
Patients with AMD Can Maximize Usable Vision
As part of vision rehabilitation training, I can teach Millie to look at an object using her peripheral vision in place of her central vision. Finding that "sweet spot" in the peripheral field is a technique called eccentric viewing (also known as Preferred Retinal Loci (PRL)) that takes some effort to learn but gets easier with practice. Already Millie has discovered that she can read the clock on her bedside table if she looks slightly to the right of it.
Millie can make the most of her remaining vision with increased, high-quality lighting. I recommend LED light bulbs that are labeled "warm" or "soft," terms that describe the color of the light, not the brightness. These yellow tones are not only easier on the eyes than the blue light of "daylight," "natural," or "cool" lightbulbs, but they will also provide better contrast so that print will tend to stand out from the page. Loss of contrast sensitivity (the ability to detect differences between light and dark areas) is a hallmark of AMD, so Millie should use contrasting colors to keep objects from fading into the background. Instead of pouring her black coffee into a navy blue mug, she might start using a light-colored cup. Millie knows white pills on a dark tray or napkin are easier to see, and she sets her pastel-colored dinnerware on a dark-colored placemat.
I encourage all my clients with dry AMD to follow their doctors’ advice about AREDs. As noted in VisionAware’s AREDS article, there are stipulations for taking the vitamin of which you need to be aware. This vitamin and antioxidant formula may help prevent the onset of the wet form of AMD. Less common than the dry form, wet or exudative AMD can result in significant vision loss due to leaking fluid or blood under the retina.
Geographic Atrophy, The Advanced Form of AMD
Some people will not notice much of a change in their vision as time goes on, but what happens if vision deteriorates rapidly? Imagine I meet Millie three years later. She has contacted my vision rehabilitation agency because her magnifying glass no longer seemed strong enough. She reported that her eyes fatigue quickly as she fights to keep her place when reading the mail. Often, she can make out only a few letters in each word. When she is reading a label on her canned goods, she can’t be sure if she is looking at a can of peas or peaches.
Millie assumed that her deteriorating vision was caused by the wet form of AMD. Instead, her ophthalmologist explained that her symptoms were typical of someone in the advanced stages of dry macular degeneration known as Geographic Atrophy (GA), the most severe and advanced form of dry AMD. GA involves patches of cells in the retina that have degenerated or died off. Atrophy refers to the degeneration of the deepest cells of the retina, called the retinal pigment epithelium (RPE). Geographic refers to the shape of the atrophied portion of the retina, which resembles the irregular outline of a land mass (geography). The RPE helps to maintain the health of the retinal photoreceptor cells, called rods and cones. These photoreceptor cells are triggered by light to set off a series of electrical and chemical reactions that help the brain to interpret what the eye sees. The degeneration of the RPE cells also leads to the death of the rods and cones.
At present, there is no medical or surgical treatment for geographic atrophy. Millie’s vision has worsened in part because she has developed a scotoma in her macula. Scotomas are often described as blind spots, but they are not actually dark areas that block our view but rather the absence of vision itself. Scotomas will cause letters in a word to disappear, and objects might suddenly vanish. For example, Millie can be looking directly at her easy chair but miss the kitten curled up against the pillow.
New Treatment for Geographic Atrophy in Clinical Trials
While the promise of stem cell therapy lies on the distant horizon, there are currently no medical treatments that can regenerate retinal cells that have atrophied. Ophthalmologists are only able to offer medications, injections, or surgeries that preserve existing vision or slow the progression of an eye disease. Patients with wet macular degeneration, for example, may benefit from injections of an anti-VEGF drug. These injections won’t improve eyesight but will inhibit the formation of new blood vessels which could lead to more vision loss.
There is no approved treatment for Geographic Atrophy (GA), but research is underway. The biopharmaceutical company Apellis Pharmaceuticals has announced that APL-2 may slow the advancement of GA. In Phase 2 Clinical Trial (FILLY) of APL-2 completed earlier this year, patients received intravitreal injections which seems to reduce the rate of degeneration. The FILLY trial involved over 40 clinical sites in the US, Australia, and New Zealand and successfully demonstrated that APL-2 is both safe and effective. Apellis has refined the protocol for Phase 3 trials, which should be underway by mid-2018.
As time goes on, there will undoubtedly be more clinical trials coming out. Learn more about how to evaluate them and protect yourself, as not all are legitimate.
Solutions for Patients with Geographic Atrophy
Millie will not likely reap the benefits of a breakthrough medical treatment that restores her vision. Still, I can assure her that vision rehabilitation training and low vision services will help her maintain independence and continue doing many of the things she used to enjoy. Millie’s 5x handheld magnifier may no longer serve her, but Millie may be able to use a video magnifier to significantly enlarge reading material. A video magnifier, also known as a CCTV, uses a camera to project reading material on a screen the size of a computer monitor. Millie may also rely on adaptive aids such as bump dots. By placing these raised tactile dots on her microwave, she can feel for the button she needs instead of relying on her vision.
Millie has excellent hearing, so she might get around vision loss by doing things auditorily. For instance, she may use a handheld recorder instead of writing out shopping lists. Millie will be surprised to learn that in addition to talking watches and clocks, there are a host of medical devices from clinical thermometers to blood pressure monitors and glucose meters that talk as well.
An avid reader, Millie can enjoy her favorite mysteries and romance novels by subscribing to the National Library Service for the Blind and Physically Handicapped. This government agency provides customers with an easy-to-use Talking Book Player that plays audiobooks on cartridges delivered to your home. The service is free and available to U.S. residents who are unable to read or use regular print materials as a result of temporary or permanent visual or physical limitations. This includes those who are blind or have a visual or physical disability that prevents them from reading or handling print materials. NLS serves patrons of all ages. Some schools and medical facilities are also eligible to apply for service as institutions.
Contact a Vision Rehabilitation Specialist Near You
Learning to adapt to life with vision loss can be overwhelming. No one should go it alone. If you or a loved one feels that they are having difficulty maintaining their quality of life because of a visual impairment, I encourage you to seek vision rehabilitation training. Search our directory to find services in your state.
Additional Information
Research on Treatments for Dry Macular Degeneration and Geographic Atrophy