Photodynamic therapy for neovascular age-related macular degeneration

Background
In neovascular age-related macular degeneration (ARMD) new vessels grow under the retina, distorting vision and leading to scarring. This is exacerbated if the blood vessels leak. Photodynamic therapy (PDT) has been investigated as a way to treat the neovascular membranes without affecting the retina.

Objective
The aim of this review was to examine the effects of PDT in the treatment of neovascular ARMD.

Search strategy
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which includes the Cochrane Eyes and Vision Group Trials Register) on The Cochrane Library (Issue 1, 2005), MEDLINE (1966 to January 2005), EMBASE (1980 to January 2005). We used the Science Citation Index to search for reports that cited relevant studies. We contacted experts in the field and searched the reference lists of relevant studies.

Selection criteria
We included randomized trials of PDT in people with choroidal neovascularization due to ARMD.

Data collection and analysis
Two authors independently extracted the data. Relative risks were combined using a fixed-effect model after testing for heterogeneity.

Main results
Two published trials were identified that randomized 948 participants to verteporfin therapy compared to 5% dextrose in water. Both trials were performed by the same investigators using largely the same clinical centers
and funded by manufacturers of verteporfin. Outcome data were available at 12 and 24 months after the first treatment. Participants received on average five treatments over two years. The relative risk of losing three or more lines of visual acuity at 24 months comparing the intervention with the control group was 0.77 (95% confidence interval 0.69 to 0.87). The relative risk of losing six or more lines of visual acuity at 24 months comparing the intervention with the control group was 0.62 (95% confidence interval 0.50 to 0.76). The results at 12 months were similar to those at 24 months. The most serious adverse outcome, acute (within 7 days of treatment) severe visual acuity decrease, occurs in about one in 50 patients.

Reviewers’ conclusions
Photodynamic therapy in people with choroidal neovascularization due to ARMD is probably effective in
preventing visual loss though there is doubt about the size of the effect. Outcomes and potential adverse effects of this treatment should be monitored closely. Further independent trials of verteporfin are required to establish that the effects seen in this study are consistent and to examine important issues not yet addressed, particularly relating to quality of life and cost.

Keywords: Photodynamic therapy, Neovascularization, Age-related macular degeneration