Limbal-conjunctival autograft healing process-early postoperative OCT angiography study

Abstract

Purpose: To assess the normal healing process of limbal-conjunctival autograft (LCA) after pterygium removal during the early postoperative period using anterior segment optical coherence tomography angiography (OCTA).

Methods: Prospective case series of seven patients undergoing pterygium removal with LCA transplantation procedure, imaged with anterior segment OCTA, and anterior segment colour photos prior to the procedure and on postoperative day (POD) 1, 3, 7 and 30. Revascularization of the graft was analysed quantitatively and qualitatively to estimate patterns of blood vessel growth. Association between revascularization to graft thickness was also investigated.

Results: On POD 1, all autografts showed either minimal flow signal or no signal at all (Mean 7.1 ± 3.3%). Regrowth of blood vessels into the graft was detected on OCTA scans on POD3 (8.7 ± 3.6%) to 7 (14.3 ± 4.1%), as nonorganised vessels formation in their appearance. Blood vessels were seen growing in a centrifugal pattern towards the surrounding conjunctiva, originating from the underlying episcleral vessels. Revascularization flow signal was seen throughout nearly all graft extent on day 30 (21.6 ± 2.2%). Graft oedema was evident on the first week (Mean 611 ± 120 μm, 695 ± 84 μm, 639 ± 96 μm of POD 1, 3 and 7, respectively), reducing substantially by day 30 (300 ± 108 μm).

Conclusions: OCTA imaging can be used to assess the LCA healing process during the early postoperative period. Revascularization occurring as early as 3-7 days post-surgery, seems to originate from the underlying episcleral vessels. Therefore, careful handling of the bare scleral surface during surgery may be prudent for achieving an adequate healing process.

Fig. 1. Colour photos and their related OCTA scans of patient 1 during POD 1, 3, 7 and 30.

A On POD1, a flow signal is already detected near the limbus, pointing to an episcleral origin. B, C On POD3 and POD7, the vessels demonstrate a centrifugal growth, with no clear connection between those vessels and the surrounding. D On POD30 blood supply to the autograft is of episcleral and conjunctival origin, with minor no signal areas indicated by the arrows.

Fig. 2. Colour photos and their related OCTA scans of patient 2 during POD 1, 3, 7 and 30.

During follow-up, a small gap between the autograft and surrounding conjunctiva was found, left for healing by primary intention (Blue arrows). A–C The flow void detected on POD1 and POD3 is followed by a network growth of blood vessel at the centre of the autograft on POD7. A clear connection between this network and the marginal conjunctival vasculature is still not seen. D A centrifugal pattern of vessel growth is evident on POD30, with small areas of absent signal, indicated by green arrows.

Fig. 3. OCT B scans of patient 2 during POD 1, 3, 7 and 30, with the corresponding en-face images to the left of each image, indicating the location of the OCT scan.

A–D Intra-conjunctival cysts are evident in the autograft during POD1 and POD3. As the revascularization process advances during POD7 and POD30, no cysts are further observed, with graft thickness gradually decreasing.