Choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) is the most common cause of legal blindness in patients over the age of 60. The neovascular lesions are usually composed of well-formed neovascularization and occult (less well-formed) neovascularization. While clinical trials have shown that some patients, mostly those with well-formed CNV, may benefit from laser photocoagulation or photodynamic therapy, at present there is no treatment for patients who have combined CNV lesions (both well-formed and occult) whose area of occult neovascularization is greater than 50% or who have other presentation of CNV such as pigment-epithelial detachment or neovascular fibrosis. Retinal histopathology of patients with choroidal neovascularization has revealed that areas of CNV are usually fed by a few smaller choroidal feeder vessels originating from the choroid or choriocapillaris. Therefore, it has been hypothesized that closure of these feeder vessels would infarct the large CNV complex. Until recently, identification of these feeder vessels has been difficult but new high speed indocyanine imaging of the choroid (Phi-motion) indocyanine green angiography (ICG) has allowed for more precise detection of these vessels. This hypothesis is being tested in a clinical trial, """"""""Feasibility Study of the Identification and Treatment of Feeder-Vessels of Choroidal Neovascularization in Age-related Macular Degeneration"""""""", by utilizing Phi-motion ICG to identify choroidal feeder vessels in patients with CNV not amenable to approved treatments. To date, recruitment of all 20 patients with various forms of vascular AMD have been completed and the 2 year follow-up period is now underway. In all enrolled patients, feeder vessels were identified. Using the Iridex milli-pulse-diode laser or a Coherent milli-pulsed yellow/green laser, photocoagulation has been performed on all these patients in an attempt to close these vessels. To aid in this study, the Center for Information Technology at the NIH has been recruited to develop image software which can help image enhanced for easier identification of the vessels and image registration to localized the precise site of treatment on a visible color fundus photograph. """"""""Image Analysis Software for Ophthalmology"""""""" has been further updated is now being routinely used in the study. This study will provide information on the feasibility of standardizing this procedure and estimating its potential efficacy.
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