No abstract

Purpose:To determine funduscopic criteria that will help predict when bridging choroidal neovascular (CNV) complexes will develop after laser retinal trauma and to define early preventive treatment targets. Methods: Ten rhesus monkeys were used and retinal lesions were produced by Nd:YAG exposures (20ns, 1-2mJ, 1064nm, min. spot size) simulating human accidental laser trauma to the central fundus. Funduscopy, fluorescein/ICG angiography, and optical coherence tomography (OCT) were conducted at day 1, 4, and 14, and at 2 and 4 months, after which animals were terminated for histologic evaluation. Predisposition for bridging fibrovascular complexes was evaluated for single hemorrhagic lesions, two small lesions showing coalescing hemorrhages, and multiple lesions involved with large field subretinal and vitreous hemorrhages. Results: All single lesions with confined subretinal hemorrhages showed elevated CNVs. All lesion sets that showed small coalescing subretinal hemorrhages formed bridging CNV scars. No bridging CNVs occurred in lesion sets involving a vitreous hemorrhage adjacent to a confined but small subretinal hemorrhage. Complex CNV formation occurred in large field subretinal hemorrhages involving multiple laser lesions. Extensive secondary photoreceptor losses occurred in large and confined hemorrhage and CNV zones. Conclusions: Trauma presenting with evidence of coalescing and confined subretinal hemorrhages between two adjacent lesions has a high chance of forming choroidal neovascular bridge complexes between the involved lesions. Release of subretinal blood through a vitreous hemorrhage reduced the chances of cross-bridging CNV formation, except for largefield subretinal hemorrhages. CNV formation may be related to the long residence time, break down products, and clearance processes of extravasated blood. Retinal detachment complications produced by the hemorrhage may further contribute to CNVs. Removal of trapped blood and curtailing angiogenesis and cellular proliferation may be helpful treatment strategies.