MAY 13, 2011
The authors retrospectively evaluated long-term visual outcomes and changes in abnormal vascular networks and polypoidal lesions in patients with polypoidal choroidal vasculopathy (PCV) who underwent photodynamic therapy (PDT). They found that long-term visual outcomes are not good due to the high frequency of recurrent polypoidal lesions, as well as enlargement of abnormal vascular networks and neovascular changes involving them.
The authors compared fluorescein agiography and indocyanine green angiography (IA) findings, fundus appearance and visual acuity before initial treatment with PDT with results three months, one year, two years and three years after treatment in 43 patients (43 eyes). They evaluated size and pattern changes of network vessels, as well as recurrence of polypoidal lesions.
The authors classified IA patterns of network vessels before PDT into two groups: 40 eyes with PCV in the narrow sense and three eyes with polypoidal choroidal neovascularization (CNV). Among the eyes with PCV in the narrow sense, enlargement of the abnormal vascular network continued in a manner similar to that before PDT in 24 eyes, transformation into polypoidal CNV developed in eight eyes and classic CNV appeared in two eyes. Among the total group of 43 eyes, polypoidal lesions recurred at three years in 33 eyes (77 percent). Mean logMAR visual acuity for all 43 eyes decreased to below the baseline at three years. The authors said that this decrease could be explained by foveal atrophy after absorption of recurrent hemorrhagic or exudative detachment.
They said the study's results confirm that PDT is not useful for stopping network vessel progression, as has been previously reported. They conclude that PDT may alter the natural progression of PCV in the narrow sense, causing enlargement or a change to polypoidal CNV as a result of ischemia and increased VEGF expression. The authors speculate that the administration of a vascular epithelial growth factor (VEGF) antagonist for PCV might minimize the adverse effect of PDT, as well as decrease the number of treatments required.