Age-Related Macular degeneration:
Age-Related Macular Degeneration (AMD) is a condition that damages the central retina, known as the macula. The retina is the light-sensing tissue that lines the inside back part of the eye. Most of the retina is devoted to peripheral vision, night vision, and sensing motion. The macula is the only area of the retina that is able to visualize fine details and provide reading and driving vision.
What are the symptoms of Macular Degeneration ?
- Blurred vision is the main symptom of AMD. It can occur in both Dry and Wet AMD. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision, while the other eye continues to see well for many years.
- Distorted vision, where straight lines appear curved, is usually due to fluid accumulating from Wet AMD, although sometimes the drusen found in Dry AMD may cause this symptom.
Prevalence of Macular Degeneration
AMD is the leading cause of legal blindness in the United States in patients over the age of 60. The incidence of AMD increases with age. Thirty percent of people over the age of 70, 40% of people over the age of 80 and 50% of people over the age of 90 are affected with some form of AMD.
Macular degeneration alone does not result in total blindness. Central and fine visual acuity is affected, but peripheral or side vision usually remains intact. For example, you can see the outline of a clock but are not able to tell what time it is. Even in more advanced cases, people continue to have some useful vision and are often able to take care of themselves.
Who is at risk for Macular Degeneration ?
- Patients with family history of AMD
- Patients with high cholesterol
- Patients who have had excessive sun exposure
Two Types of Macular Degeneration
“Dry” Macular Degeneration (Atrophic, Dry AMD)
- Affects the majority of people with AMD.
- Vision loss is usually gradual.
- Caused by degeneration of the sensitive cells beneath the retina allowing for the accumulation of “drusen.”
“Wet” Macular Degeneration (Exudative)
- Accounts for 10 to 15% of people with AMD.
- Abnormal blood vessels form under the macula and leak fluid or blood.
- Vision loss may be rapid and severe.
- Leakage results in distorted or blurred central vision.
How is Macular Degeneration Diagnosed?
Many people do not realize that they have a macular problem until blurred vision become obvious. Your retinal doctor can detect early stages of AMD and diagnose the type of AMD by performing:
- A complete dilated eye exam
- A vision test in which you look at a chart that resembles graph paper (Amsler grid)
- An examination of the macula with special instrumentation
- Optical Coherence Tomography (OCT)- Non-invasive imaging of the macula at the microscopic level
- Fluorescein Angiography (FA) – Tests the retinal circulation to identify the abnormal blood vessels and diagnose Wet AMD. A vegetable-based dye is injected into your arm and photos of your retina are taken.
Treatment of Macular Degeneration
Currently, there is no cure for “dry” macular degeneration. Southern Vitreoretinal Associates is enrolling patients in a clinical trial of Lampalizumab to assess whether it helps to slow the progression of an advanced form of dry AMD, termed geographic atrophy.
Antioxidant vitamins can reduce the rate of vision loss from AMD by 25% each year. Amsler grid monitoring can help detect progression from dry AMD to wet AMD.
Treatment for the wet form of macular degeneration involves injecting a medication into the eye called a “VEGF inhibitor.” The three commonly used VEGF inhibitors are Avastin, Lucentis, and Eylea. Lucentis and Eylea are FDA approved while Avastin is used off label.
Southern Vitreoretinal Associates is enrolling patients in a clinical trial of Fovista (a PDGF inhibitor) to assess whether the combination of Fovista and Avastin or Eylea is more effective than Avastin or Eylea by itself.
The medication is injected directly into the eye with a tiny needle. The treatment takes just a few minutes and is painless, and often needs to be repeated after a month or longer. This treatment halts the cycle of vision loss in 90% of patients, and many patients eventually have improvement in vision