Clinical observations supporting a theoretical model of choriocapillaris blood flow in treatment of choroidal neovascularization associated with age-related macular degeneration

Abstract

PURPOSE: To report clinical observations consistent with conclusions from a previous theoretical investigation indicating that photocoagulation of choroidal neovascularization (CNV) efferent vessels can be, in some instances, an effective treatment. DESIGN: Interventional case series. METHODS: In five eyes with age-related macular degeneration (five patients with mean age ± SD of 65 ± 11 years, range 55–79 years) requiring treatment of CNV. In each case, the appropriate treatment was location and photocoagulation of the CNV efferent vessels, since the afferent vessels were not identifiable or were located beneath the fovea. Targeted vessels were determined to be draining vessels by analysis of pretreatment high-speed indocyanine green (ICG) angiograms, and successful vessel closure by photocoagulation was demonstrated by posttreatment ICG angiograms. The eyes subsequently were followed from 2 to 12 months. RESULTS: After photocoagulation of efferent vessels, CNV-related retinal edema was significantly reduced or resolved within 1 to 4 days. Visual acuity became stabilized in three eyes and improved in two eyes. In a few days, metamorphopsia disappeared in four of the eyes and was stable for a period longer than the duration of the associated efferent vessel closure. Initial efferent vessel closure by photocoagulation persisted on average for 7 to 15 days, after which additional treatment was required. It is significant that in no case did hemorrhage result from the photocoagulation treatment. CONCLUSIONS: These observations are consistent with the earlier theoretical study prediction that photocoagulation of efferent CNV vessels can be effective in reducing CNV-associated edema. That no hemorrhage was induced by photocoagulation is consistent with the theoretical concept that there appears to be no direct hydrostatic connection between the CNV and its afferent vessels. Rather, that connection appears to be a functional one made through the choriocapillaris, which may dissipate excess CNV hydrostatic pressure produced by occlusion of a draining vessel. However, this finding is not intended to be a recommendation to attempt CNV efferent vessel photocoagulation.