Dr. Justin Kanoff on treating vision-robbing macular degeneration

“Today we have treatments for wet macular degeneration that are fantastic.”

Age-related macular degeneration (AMD) is the leading cause of severe vision loss in older adults, affecting more than 10% of those over the age of 75. Its victims live with a large blurry or blind spot at the center of their field of vision, making basic everyday activities—reading, driving, navigating stairs—agonizingly difficult.

“Early detection and timely treatment of AMD can help slow the progression of vision loss, and in some cases even improve it, which is why having an eye exam at least once a year is very important,” said board-certified retina specialist Justin Kanoff, MD, during a free online health lecture.

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Watch Advances in treating macular degeneration 

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Symptoms of AMD

AMD is caused by the aging and deterioration of a small area of the retina, known as the macula. The macula controls your central vision and your ability to read, recognize colors or see the fine details of straight-ahead objects.

Symptoms of AMD include the following:

• Distortions in vision (straight lines appear distorted, text can appear wavy or blurred)
• Dark, blurry areas or whiteout that appears in the center of your vision
• Difficulty seeing details in low-light levels
• Loss of color vision or intensity
• Extra sensitivity to glare
• Change in your perception of color
• Difficulty recognizing faces

“It's almost always in both eyes but oftentimes patients are only aware of the symptoms in one eye,” Dr. Kanoff explained. “As the disease progresses, you might have trouble distinguishing faces. The spot in the center of the vision expands, and it can make it very difficult to recognize faces or other images that you're trying to focus on.”

Risk factors

Risk factors for macular degeneration are divided into two categories: well-established risk factors and possible risk factors.

Established Risk Factors

• Older age (> 60 years)
• Family history (three-fold higher)
• Cigarette smoking
• Low dietary intake or body concentrations of anti-oxidants, vitamins and zinc

Possible Risk Factors (research still ongoing)

• Female sex
• Light-colored iris
• Cardiovascular disease
• Obesity, high cholesterol and lipids, hypertension
• Sun exposure

When asked by patients whether cataract surgery is a risk factor he stated, “I tell them that you can feel comfortable having cataract surgery and that this is not going to affect your AMD or increase your risk for it. It’s actually quite the opposite. Cataract surgery is often extremely beneficial for patients with macular degeneration because it can improve contrast sensitivity, which is the ability to read letters that are printed on a similar shade background.”

He added, “One caveat is that patients with AMD should avoid the multifocal or other premium types of lenses that try to give distance and near vision because those lenses can decrease contrast sensitivity and could compound some of the difficulties with AMD.”

Ways to lower your risk
Dr. Kanoff explained that no one knows exactly what causes AMD. But currently the best way to protect your eyes from AMD is to do the same things you would do to avoid many other chronic diseases.

Research shows that AMD occurs less often in people who avoid smoking (which happens to double your risk), get regular exercise and eat nutritious foods. Food choices that can help reduce your risk include dark-green leafy vegetables, eggs, carrots or any food high in beta-carotene, almonds, and fruits high in vitamin C. Also, eating fatty fish one or more times a week may reduce your risk for AMD.

Types of AMD

There are two types of AMD: dry (atrophic) and wet (exudative/neovascular).

Dry Type

“Dry AMD is the most common form of AMD, accounting for about 85 to 90 percent of cases,” Dr. Kanoff stated.

He said that over a period of years, dry AMD can progress through three stages:

• Early – You are unlikely to notice any symptoms at this stage, which is characterized by the presence of medium-sized drusen (yellow deposits beneath the retina).
• Intermediate - At this stage, you may notice some minor vision changes, along with larger drusen and/or pigment changes in the retina.
• Late - There is severe vision loss at this stage.

“Since in its early stages dry AMD does not have any symptoms, a comprehensive dilated eye exam of the back of the eye is the only way to diagnosis it,” Dr. Kanoff explained.

Slowing down the progression of dry AMD

“Unfortunately, at this point in time, there aren't a lot of great treatments for the dry form of AMD,” Dr. Kanoff said. “Even though there are no cures for dry AMD, a special combination of nutritional supplements can potentially slow down the disease’s progression.”

Two large clinical trials conducted by the National Eye Institute (NEI)—the Age-Related Eye Disease Study (AREDS; 2001) and a follow-up study called AREDS2 (2013)—found that a special formula of nutritional supplements could reduce an AMD patients' risk of progressing to the advanced stage by about 25 percent over a five-year period. However, so far there is no evidence that supplements benefit patients in the early stage.

The original AREDS formula included beta carotene, which was later found to be linked to higher lung cancer rates in smokers. In the follow-up AREDS2 study, researchers examined the formula without beta carotene, replacing it with antioxidants lutein and zeaxanthin and lowering the zinc content.

The AREDS2 special formula includes:

• Lutein (10mg)
• Zeaxanthin (2mg)
• Vitamin C (500mg)
• Vitamin E (400IU)
• Zinc (80mg)
• Copper (2mg)

Although both AREDS and AREDS2 formulas are available over the counter, it’s best to consult your doctor before you start taking either of them. Determining the best formula for you depends on your medical history, type of AMD and stage of the disease.

“Patients ask, ‘Should everybody be taking these eye vitamins to try to prevent macular degeneration?’ Unfortunately, the studies have not shown that these vitamins are helpful in preventing the onset of AMD,” said Dr. Kanoff. “They are really only helpful in preventing progression of the disease once it starts. The only people who need to be on these eye supplements are patients who have been diagnosed with macular degeneration.”

Wet type

About 10% of dry AMD cases will transition to the wet form. Moreover, 35% of people with wet AMD in one eye will get wet AMD in the other eye. Individuals with high blood pressure are at higher risk of transitioning.

“We want to know about a transition to wet macular degeneration as soon as possible because the wet form is highly treatable,” Dr. Kanoff noted.

With the wet type of AMD, abnormal growth of blood vessels underneath the retina. These blood vessels break through the macula, causing bleeding and swelling that leads to the loss of central vision. Wet AMD progresses very rapidly and vision loss is severe.

Treatments for wet AMD

“Luckily, today we have progressed to wet AMD treatments that are fantastic,” Dr. Kanoff stated enthusiastically. Treatments include the following:

• Photodynamic therapy or pdt uses a cold laser that activates medication for AMD. The medication is injected intravenously and circulates to the back of the eye. Then a cold laser directed into the eye activates the medicine and seals off the abnormal blood vessels. “However, since it just slow downs the progression of wet AMD—and not reverse it—it’s used only in selected cases,” he said.

• Eye injections – “Currently, the most effective clinical treatment for wet AMD is anti-vascular endothelial growth factor (anti-VEGF) therapy,” said Dr. Kanoff. “This involves a periodic eye injection of a chemical called an anti-VEGF, which hinders the growth of new blood vessels behind the retina and keeps it free of blood leakage."

Using a syringe, anti-VEGF medication is injected into the center part of the eye, which then causes the problem blood vessels to regress and stop leaking. There are currently four medication options available: Avastin, Lucentis, Eylea and Beovu.

“With these treatments over the long term, there's a 95% chance of patients maintaining their vision and there's a 30-to-40% chance of having a significant improvement in vision. This is really a game changer in the treatment of wet AMD, and has really been a miracle for patients,” Dr. Kanoff declared.

He added, “Most injections can be done with a minimal of discomfort. Most patients typically just feel a pressure sensation on their eye. The eye will be irritated for about 24 hours, but for the vast majority of patients it is a very, very minimal discomfort.”

Home monitoring

If you’ve been diagnosed with AMD, Dr. Kanoff said that you may be given an Amsler Grid, a grid of horizontal and vertical lines that monitors a person’s central visual field. Used at home as an early warning system for changes in your vision, you’d view the grid and check to see whether lines on it look wavy or distorted, or whether areas of the grid are missing.

He then explained how ForeseeHome is an at-home monitoring device that can help catch any progression from dry to wet AMD. Using a mouse and an interactive computer, you'd take a daily test that checks for tiny changes in your vision. The system then sends monthly reports to your doctor’s office.

“What it's useful for is helping patients monitor at home whether there are any changes in their vision, which might suggest that the disease has progressed into the wet form.”

What’s on the horizon for treatment

Dr. Kanoff stated that there are multiple medications in clinical trials both for early and late stages of AMD, and they take many forms—from eye drops, oral pills and eye injections to different surgical treatments. But probably one of the most cutting-edge and exciting treatment is different types of stem-cell-derived RPE.

“There's been some good data on transplanting RPE cells, which are cells that live underneath the retina. If we're able to grow new layers of this tissue in a lab and transplant them into the eye, this can potentially restore function,” Dr. Kanoff said. "Also, the FDA recently approved a port delivery system. It's a little device that is implanted in the wall of the eye and essentially serves as a reservoir for medication. Instead of having the injections every month, this device can be implanted and filled once every six months or once a year and then the medicine is slowly delivered to the eye over time.”

Other treatments currently in clinical trials include:

• Oral medication and eye drops
• Multiple new injections for longer lasting medications
• Gene therapy, which target the biological pathways that lead to disease

If you wish to be screened or treated for AMD, schedule an appointment with Justin Kanoff, MD by calling 303-772-3300.

Click here to view/download a PDF of slides shown during “Advances in Treating Macular Degeneration.”

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