Corneal angiography for guiding and evaluating fine-needle diathermy treatment of corneal neovascularization

Purpose To investigate the outcome of selective occlusion of the afferent vessel of corneal neovascular complexes (CoNVs), using angiographically guided fine-needle diathermy (FND). Design Retrospective interventional case series. Subjects Patients with CoNV unresponsive to topical steroid therapy. Methods Visual acuity, color images, and fluorescein angiography and indocyanine green angiography were measured before and after FND with a minimum of 3 months of follow-up. The number of afferent vessels crossing the limbus, time to fluorescein leakage, area, and geometric properties of the CoNV were determined using an in-house automated program written in numerical computing language (MatLab R14; The MathWorks Inc., Natick, MA). The location of the afferent vessel was identified from the angiographic images and marked at the slit lamp using a needle to make a cut to the depth of the vessel. We then applied FND using an electrolysis needle. Main Outcome Measures Area of CoNV. Results Thirty patients underwent FND for CoNV that had not responded to treatment with topical steroids. The CoNV was associated with previous microbial keratitis (n = 26), intrastromal corneal ring segments (n = 2), ectodermal dysplasia (n = 1), and corneal choristoma (n = 1). Duration of CoNV was >6 months in 23 patients (77%), between 3 and 6 months in 3 patients (10%), and <3 months in 5 patients (13%). The number of afferent vessels per CoNV ranged from 1 to 3, with a mean diameter of 40 μm (standard deviation [SD], 10 μm) and mean time to leakage from apical vessels was 44.22 seconds (minimum, 27.43 seconds; maximum, 63.59 seconds). The number of FND treatments that were required was 1 for 20 patients (66.6%), 2 for 8 patients (26.6%), and 3 for 2 patients (6.6%). After FND, the area of CoNV reduced by 1.80 mm2 (SD, 1.40 mm2), from 2.42 (SD, 1.59) to 0.62 mm2 (SD, 0.73 mm2) up to 12 weeks postoperatively (P < 0.01). Conclusions The differentiation of afferent and efferent vessels using corneal angiography enables treatment to be selectively applied to the afferent vessels; there are usually 1 to 2 for each CoNV complex.