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Dr. Justin Kanoff on Vision-Robbing Macular Degeneration

  • Category: General
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  • Written By: Boulder Community Health
Dr. Justin Kanoff on Vision-Robbing Macular Degeneration
Age-related macular degeneration (AMD) is the leading cause of vision loss in older adults, affecting more than 10 percent 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.

Justin Kanoff“As of right now, there is no cure for AMD. However, early detection and timely treatment of AMD can help slow the progression of vision loss, which is why regular exams are very important,” BCH retina specialist Dr. Justin Kanoff told a crowd of more than 200 people during a free health lecture held in Boulder.

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.

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, 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 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 said.

As the disease progresses, you may experience:

  • Wavy or blurred vision
  • Visual distortion such as straight lines for sentences on a page appearing bent
  • Extra sensitivity to glare
  • Loss of color vision or intensity
  • Difficulty seeing details in low-light levels
  • Problems recognizing faces

Treatments to slow vision loss

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,” Dr. Kanoff warned.

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 can monitor 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.

Wet Type

With the wet type of AMD, 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.

“Ten percent of dry AMD cases will convert to the wet form. And, individuals with high blood pressure are at higher risk,” Dr. Kanoff stated.

He then explained how ForeseeHome is an at-home monitoring device that can help catch any progression from dry to wet AMD. You take a daily test to check for tiny changes in your vision. The system then sends monthly reports to your doctor’s office.


“Currently, the most effective clinical treatment for wet AMD is 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. Studies show high rates of success for maintaining a patient’s current level of vision and that it may even improve vision.”

He said in select cases, Photodynamic Therapy (PDT) can be added as a second-line treatment or supplement to injections.

“PDT involves injecting a light-sensitive drug into your arm. Then a cold laser directed into the eye activates the medicine and seals off the abnormal blood vessels,” Dr. Kanoff explained. However, this treatment isn’t a cure and doesn’t restore vision that has already been lost. But one large clinical trial showed that PDT delayed or prevented further loss of vision during a one-year follow-up with patients.

Ways to Lower Your Risk

Dr. Kanoff said 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 should 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.

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

View PowerPoint slides from Dr. Kanoff’s lecture on “Advances in Treating Macular Degeneration.”

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