Optical Coherence Tomography Angiography for Evaluation of Reperfusion After Pterygium Surgery

Abstract

PURPOSE: 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.DESIGN: Prospective, interventional case series. METHODS: Ten patients undergoing pterygium excision and femtosecond laser-assisted CAG transplantation were included. OCTA was performed at 1 week, 1 and 3 months 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. RESULTS: No intraoperative and postoperative complications occurred. Reperfusion of the CAGs was observed at 1 week, 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 1 week and 1 month, and was 9.8±1.8 % and 11.9±1.9 % between 1 and 3 months, at the CAG and underlying episcleral levels, respectively. All the CAGs were well-perfused at 3 months. The vessel regrowth density was significantly and strongly correlated with the changes of CAG thickness in a negative relationship (g [ -0.94, P [ 0.019). At the harvested site, the vascular network of episclera was not affected, and the conjunctival vascularization was restored at 1 month. CONCLUSIONS: 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.

Femtosecond Laser-assisted Preparation of Conjunctival Autograft for Pterygium Surgery

“…We have also previously evaluated the conjunctival re-reperfusion rate at the harvested site using OCT angiography (OCTA). The conjunctival vascularization was restored at 1 month, and the underlying episcleral vascular network was not affected by the laser 25 . Table 3.…”

“…During the one-month follow-up, no postoperative complications or recurrences were observed 22 . Moreover, there was no collateral thermal damage resulting from the laser pulses seen in the histological sections on the CAGs 24 , and the vessel revascularization over the whole CAG was complete within 3 months after transplantation 25 . With the increasing popularity of femtosecond lasers in modern anterior segment surgery, femtosecond laser-assisted CAGs preparation can be an additional application in centers that are already equipped with a laser.…”

Application of Femtosecond Laser in Anterior Segment Surgery

“…FSL can also enable automated, quick, and reliable preparation of an ultrathin conjunctival autografting, which might be helpful for further standardization of a surgical procedure for conjunctival reconstruction [119]. Our studies have shown the efficacy of FSL in the preparation of an ultrathin conjunctival autografting after excision of pterygium or conjunctival melanosis (Figure 4) [119][120][121][122][123]. Our study using a primate model suggested that biological corneal inlays derived from lenticules extracted from SMILE might be a viable option for the management of presbyopia ( Figure 5) [124].…”

Clinical Applications of Optical Coherence Angiography Imaging in Ocular Vascular Diseases

“…The systems also have poorer detection of vessels with minimal flow since erythrocytes are slower in small calibre vessels and may be below the threshold of detection, which is dependent on the A-scan rate of the system [80]. OCTA is also unable to differentiate between arteries and veins [84]. As OCTA algorithms are optimized for the posterior segment, which has mainly transverse flow in vessels, anterior segment vessels with axial flow may also not be detected [85].…”