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 mm(2) (SD, 1.40 mm(2)), from 2.42 (SD, 1.59) to 0.62 mm(2) (SD, 0.73 mm(2)) 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.