Photodynamic Laser (Visudyne)
Photodynamic laser is the first treatment approved by the FDA to seal up leaking blood vessels under the retina. By using an activated drug, rather than the heat from the laser, this treatment can seal abnormal, leaking blood vessels without burning the overlying retina. The treatment is successful at reducing vision loss in patients with wet macular degeneration and blood vessel growths under the central retina (macula). Unfortunately, on average, patients treated with photodynamic laser do not improve. They lose less vision then they would have lost had they not been treated.
Now we have better treatments like Lucentis and Avastin that improve vision in most patients with wet macular degeneration. Visudyne is not used much today. It may be useful in conjunction with other therapies at reducing the number of times patients need to be treated. It may also be useful in treating some forms of wet macular degeneration that do not respond well to the newer therapies.
The treatment involves injection with a photosensitizing drug, visudyne, and then treatment with a low energy laser to activate the drug and seal up the abnormal wet macular degeneration blood vessels.
The schematic photo to the left shows the drug circulating in the abnormal vessels under the retina and how, once activated by the laser, the drug seals up the abnormal vessels causing their destruction.
Photodynamic laser usually needs to be repeated every 3 to 6 months for a few years to have a permanent effect. Because the visudyne injected intravenously takes a few days to clear the body, patients need to completely avoid sunlight for 3 days after treatment. If the skin of a patient is exposed to powerful light, like the sun, soon after treatment, they can develop a severe burn.