Optical Coherence Tomography Angiography for Evaluation of Reperfusion After Pterygium Surgery

Abstract

To describe the use of optical coherence tomography angiography (OCTA) to quantitatively monitor the conjunctival graft revascularization after pterygium excision and conjunctival autograft (CAG) transplantation. Prospective, interventional case series. Ten patients undergoing pterygium excision and femtosecond laser-assisted CAG transplantation were included. OCTA was performed at 1week, 1 and 3months postoperatively at the CAG transplantation site and harvested area. The vessel density at three different depths: conjunctival epithelium or CAG epithelium, conjunctival stroma or CAG stroma, and episclera, was evaluated and quantified. The revascularization rate was assessed and correlated with the postoperative CAG thickness. No intraoperative and postoperative complications occurred. Reperfusion of the CAGs was observed at 1week, and early reperfusion within the first month accounted for more than half of graft revascularization. The vessel regrowth density was 9.6±2.6 % and 11.1±2.8 % between 1week and 1month, and was 9.8±1.8 % and 11.9±1.9 % between 1 and 3months, at the CAG and underlying episcleral levels, respectively. All the CAGs were well-perfused at 3months. The vessel regrowth density was significantly and strongly correlated with the changes of CAG thickness in a negative relationship (γ = -0.94, P = 0.019). At the harvested site, the vascular network of episclera was not affected, and the conjunctival vascularization was restored at 1month. OCTA is a promising tool to evaluate the vascularization or revascularization of conjunctiva, conjunctival graft and episclera, in a quantitative and serial manner, helping in diseases diagnosis and treatment monitoring. The graft revascularization rate was predictive of postoperative graft deswelling.