Question: What is laser photocoagulation, when is it used to treat diabetic retinopathy and what are the risks/benefits of this procedure?
Answer: Laser treatment uses a laser, which is a source of very intense light that can be very precisely aimed and focused, and it's used like a cautery to cauterize tissues inside the eye. Patients with diabetic retinopathy who develop swelling in the eye are treated with laser. The swelling comes from leaky blood vessels near the center of the retina. The center of the retina is called the macula, and that's where our sharpest vision comes from.
So when the swelling gets in or near the macula, it can reduce our vision, and that's when the doctor uses the laser. It's been shown in large studies in the United States as well as abroad that laser treatment for swelling in the retina can reduce the risk of visual loss by about one half, or about 50 percent. The risk of the treatment is very, very low. It's rare for it to produce any significant side effects. People are blurred for one day.
Occasionally, maybe 1 percent of people may have a slight reduction in vision from the laser, but otherwise it's pretty safe. The other time that laser is used is when blood vessels grow on the retinal surface and they don't belong there. They're abnormal vessels. Those vessels are very fragile, and they can easily break and bleed into the jelly of the eye. And as you can imagine, the blood in the jelly obstructs your vision.
In those cases, the laser is also used to cauterize the retina and cause the blood vessels to shrink up or go away. In these cases laser has also been shown to reduce the risk of serious visual loss by about 50 percent, or one half. Patients who have this kind of laser for abnormal blood vessels will have a reduction somewhat of their peripheral vision or side vision. Most people don't really notice it because it's not that significant. And in addition, people who have the laser will have a bit of a reduction in their ability to see in dim light.
But again, that's usually not a big problem for most patients. Some people who have the laser for abnormal vessels, paradoxically, will develop swelling in the center of the retina. There are ways now that we can prevent that by administering certain medications before doing the laser, thus making that also a very safe procedure.