Serial optical coherence tomography angiography for corneal vascularization

Recently, optical coherence tomography angiography (OCTA) has been used to successfully delineate vessels within the retina. This current study aims to assess corneal vascularization secondary to herpetic keratitis pre- and post-treatment using serial OCTA imaging adapted for the anterior segment. All eyes were scanned using the split-spectrum amplitude decorrelation angiography (SSADA) algorithm on the AngioVue OCTA system (Optovue Inc. Fremont, CA, USA) with an anterior segment lens adapter. Multiple scans in the regions of interest (ROI) before and after treatment were analysed to assess change in corneal vascularization in response to each treatment modality. We analyzed a total of 12 OCTA scans in three eyes with corneal vascularization, comparing images pre- and 3 months post-treatment. We found that the OCTA was able to detect a significant decrease in area of vascularization in all eyes: including fine-needle diathermy (48 +/- 7 to 41 +/- 5 %, P = 0.048), subconjunctival bevacizumab (45 +/- 7 to 38 +/- 5 %, P = 0.015) and systemic steroid treatment following graft rejection (38 +/- 1 to 32 +/- 2 %, P = 0.003). Our preliminary study of serial OCTA scans suggests that this may be a useful tool for objective quantification of corneal vascularization. Future development of image processing software will be needed for clinical use or trials to evaluate anti-vascular therapies.