There are two basic types of macular degeneration: “wet” and “dry.” Approximately 10-15% of the cases of macular degeneration are the “wet” (exudative) type.
It is called “wet” due to the development of leaky blood vessels that have grown to compensate for the functional problems created by the dry form of AMD. The excessive growth of these leaky blood vessels is called neovascularization, which is why wet AMD is also called neovascular AMD, or nAMD for short.
The transition to wet AMD can be sudden, accompanied by dramatic central vision loss.
This can be avoided to a great extent if you work closely with your eye care specialist to monitor the progression of your dry AMD (both at home, using self-testing tools, and through regular office visits) and report any changes to your vision right away. The same holds true for monitoring your wet AMD and not missing treatment appointments, which can allow the disease to progress.
What the patient might see:
With the “wet” type, patients may see a dark spot (or spots) in the center of their vision due to blood or fluid under the macula. Straight lines may look wavy because the macula is no longer smooth. Side or “peripheral” vision is rarely affected. However, some patients do not notice any such changes, despite the onset of neovascularization (1). Therefore, periodic eye examinations are still very important for patients at high risk.
Animation of Wet and Dry Macular Degeneration
Treatments for Wet AMD
Treatments exist for wet AMD that can stop the development of leaky blood vessels by interfering with the body’s signaling for new blood vessel growth. These treatments require injections into the eye of drugs called anti-VEGF agents, at regular intervals that you establish with your eye doctor. Over time, based on how you respond to the treatments, your retina specialist may suggest that the time between them can be extended. A new class of treatments, that combine anti-VEGF agents with agents that also reduce leakage from existing blood vessels, is becoming available.
While treatments for wet AMD are designed to preserve current sight and prevent further vision loss, some patients can experience improved visual acuity as fluids that have leaked behind the retina are reabsorbed and the macula resumes its normal position.
1. AM Fine, Earliest symptoms caused by neovascular membranes in the macular. Arch Ophthal. 1986;104:513-4.
2. MG Maguire, Natural history. JW Burger, SL Fine, MG Maguire, eds. Age-related Macular Degeneration. St. Louis: Mosby: 1999;17-30.
3. Macular Photocoagulation Study Group. Risk factors for choroidal neovascularization in the second eye of patients with juxtafoveal or subfoveal choroidal neovascularization secondary to age-related macular degeneration. Arch Ophthal. 1997;115:741-7.