Photodynamic therapy for neovascular age-related macular degeneration

Abstract

Background: In neovascular age-related macular degeneration (AMD) 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.

Objectives: The aim of this review was to examine the effects of PDT in the treatment of neovascular AMD.

Search strategy: We searched CENTRAL (Issue 1, 2007), MEDLINE (1966 to March 2007), EMBASE (1980 to March 2007). We contacted experts in the field and searched the reference lists of relevant studies.

Selection criteria: We included randomised trials of PDT in people with choroidal neovascularisation due to AMD.

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

Main results: Three published trials were identified that randomised 1022 participants to verteporfin therapy compared to 5% dextrose in water. The TAP and VIP trials were performed by the same investigators using largely the same clinical centres 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 risk ratio 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 risk ratio 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 seven days of treatment) severe visual acuity decrease, occurs in about one in 50 patients. Some outcomes from the more recent VIM trial could be included in the meta-analysis but have not greatly altered the findings.

Authors' conclusions: Photodynamic therapy in people with choroidal neovascularisation due to AMD 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. However, the advent of new interventions for AMD make this unlikely.