Laser Treatment

Thermal laser treatment is one treatment that has proven beneficial in treating macular degeneration. The Macular Photocoagulation Study (MPS) was a landmark study conducted by the National Eye Institute. The MPS provided valuable data which forms the basis for current treatment of macular degeneration. All potential treatments under investigation are judged in light of the MPS results.

In the Macular Photocoagulation Study several thousand patients with choroidal neovascularization (CNV) due to macular degeneration were randomly assigned to one of two treatment groups. One group had laser treatment. The other group was observed without any treatment. The data showed a significant benefit to laser treatment. Patients who received laser treatment had less vision loss than those who were untreated.

However, there are significant limitations to the laser treatment. On average, treated patients experienced less vision loss than untreated patients – but they still lost some vision. Laser treatment wipes out the abnormal blood vessel growth, but it also damages the normal retina in that spot. Wherever the laser treatment is applied, the patient is left with a blind spot. The size and location of this blind spot will vary with where the abnormal blood vessels were.

If the abnormal blood vessels were small, and not too close to the macular center, there may only be a small blind spot that the patient does not even notice. However, it is much more common for the abnormal blood vessels to be large and close to the center of the macula. Laser treatment then results in a noticeable – and bothersome – blind spot. Still, this blind spot is often not as bad as the vision damage from the untreated blood vessels would be. That’s why laser treatment for macular degeneration is a very common procedure.

Another limitation to treatment is that only some patients meet MPS criteria for treatment. The Macular Photocoagulation Study had specific requirements regarding the type of leakage that could be treated. Patients had to have classic well-defined leakage to qualify for treatment. This means that the abnormal blood vessels had to be clearly visible on the angiogram, with sharply defined borders. Unfortunately, in the majority of patients the leakage is occult or ill-defined. Those patients are not candidates for treatment according to the MPS criteria. Furthermore, in other patients, blood under the retina blocks us from seeing where the leakage is coming from. Only about 20 percent of patients will have angiograms that indicate treatable leakage.

Laser treatment is an outpatient procedure that causes little discomfort. Even though the laser treatment itself does not take very long, the total entire time spent in our office will be about 2 hours.