Age-related macular degeneration (AMD) is a degenerative, often progressive condition that affects the central retina (macula).  There are two major forms, dry and wet which will be discussed below.  AMD generally causes painless central vision loss and distortion.  In general, peripheral vision is unaffected.  Often the disease is slowly progressive, especially with Dry AMD, but rapid vision loss can occur with Wet AMD.

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What are risk factors for AMD?

The biggest risk factor is age, as AMD is extremely rare under the age of 50 and mostly affects people over 70 or 80.  Family history and genetics can play a role as well, and AMD is more common in caucasians.  Tobacco use is a big risk factor as well, and quitting can be very helpful to slow disease progression.

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Dry Age Related Macular Degeneration

Dry AMD encompasses a large range of clinical severity.  As an eye ages, cell waste material can accumulate underneath the retina as deposits called drusen.  Although it can be of no significance for eyes to have a mild amount drusen, as more drusen accumulate in the macula slow vision loss can occur.  In some cases, very damaged areas of retina can atrophy and cause central blind spots which if located in center of  the macula (the fovea) can cause severe central vision loss.    

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What is the treatment for Dry AMD?

Although there is a lot of active research in the area, current treatment options for dry AMD are limited.  The mainstay of treatment is periodic exams (generally once or twice a year) to monitor for conversion to Wet AMD.  Tools to help monitor vision at home are essential as well (an Amsler grid or electronic devices such as Foresee Home).  In intermediate to advanced cases, your doctor may recommend AREDS2 vitamins, which are over the counter and can help reduce the risk of conversion to Wet AMD.  

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Wet Age Related Macular Degeneration
In the wet form of AMD, abnormal blood vessels grow under the retina.  In a healthy eye, a layer underneath the retain called the retina pigment epithelium (RPE) separates the retina from its blood supply (the choroid).  The drusen deposits in AMD can damage this RPE layer and allow blood vessels from the choroid to grow underneath the retina (a process called choroidal neovascularization, or CNV).  A good example is weeds growing through cracks in a concrete patio or sidewalk.  These blood vessels can leak or break, resulting in blood or fluid collections. If this occurs behind the central retina, rapid vision loss and distortion can occur. If treatment is delayed, blood or fluid can be toxic to the retina, resulting in permanent damage which cannot be fully treated.

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What is the treatment for Wet AMD?

Vision loss occurs much more rapidly in Wet AMD, and without timely treatment permanent vision loss can develop within weeks to months.  The primary treatment for wet AMD is injection of medication into the back part of the eye, known as the vitreous.   These injections have revolutionized treatment for AMD and allow to stabilization of vision and vision improvement in many patients.  The leakage of blood and fluid in wet AMD is caused by a hormone called VEGF (vascular endothelial growth factor). The medicines injected into the eye block this hormone (anti-VEGF medicines).   Several different medications exist, with more being developed each year. 

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Anti-VEGF injections do not cure wet AMD. The injections help reducing bleeding and subretinal fluid and regress the neovascularization.   Ongoing injections over 1-2 years are usually needed to control the disease, with some patients requiring an even longer treatment duration.  

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