10% of the adult population over the age of 65 years develop macular degeneration. Approximately 6% of the patient population will develop choroidal neovascularization as a complication ("wet degeneration") and have only been able to be managed by either thermal laser photocoagulation or by submacular surgical excision in order to limit the damage. Laser therapy has only been offered to 10% of affected individuals and results in a permanent scotoma in the area of treatment.

The goal has been to develop a target dye that can be taken up by the choroidal neovascularization process (under the retinal photoreceptors) and then irradiate the activated tissue with a low intensity (non-thermal) laser that will be selectively taken up by the labeled tissue and selectively ablate the neovascular process without damage to the overlying retina. The illustration below shows the infiltration of abnormal new vessels through the Bruch's membrane and into the potential space under the retinal photoreceptors.

After injection of a photosensitizing dye (verteporfin; Visudyne), the dye complexes with LDL lipoproteins in the serum and is selectively taken up by the abnormal neovascular tissue as shown below. This process takes up to 15 minutes from the time of intravenous injection.

The dye is then activated by use of a red light (689 nm) applied after 15 minutes and the free radicals released during the photochemical reaction induce involution of the abnormal vessels.

By limiting the treatment effects to the abnormal neovascular process, the overlying retinal photoreceptors are not affected and a short term improvement in vision is found.

Eligible patients must have neovascular processes with >50% classic lesions, must be <5400 microns in diameter, and the best corrected vision must be 20/40 or worse. 609 patients have been randomly assigned and studied prospectively with a positive treatment benefit observed (vision stabilization or improvement).

Drawbacks include the need for retreatment (every 3 months) and the cost of the Visudyne (approximately $1200 per dose). It must also be stressed that the other 90% of subfoveal choroidal neovascular membrane processes which are <50% classical on angiography or which are occult (over ½ of cases) are not eligible for PDT (photodynamic therapy).

Visudyne (verteporfin) was recently approved by the FDA and treatment in our office is now available. Other forms of therapy include thermal laser photocoagulation, subfoveal surgery, and TTT. All of which are reasonable and accepted standards of care for subfoveal choroidal neovascularization in the setting of age-related macular degeneration.

This represents a paradigm shift in our approach to the therapy of classic subfoveal choroidal neovascularization in age-related macular degeneration. We anticipate other dyes and matching laser treatments to become available over the next few years.

At the Retina Eye Center, we are proud to offer this significant advance in therapy to patients.