Lymphatic corneal neovascularisation affects graft survival in high-risk corneal transplantation.

Objectives: Corneal neovascularisation (CoNV) is a major risk factor for corneal allograft rejection and failure. This study assessed the impact of preoperative lymphatic and haematic vascularisation of the graft bed on graft survival in a clinical setting.

Methods and analysis: This retrospective study included patients with histologically confirmed CoNV (positive staining for CD-31) who underwent penetrating keratoplasty (PK) between 2008 and 2023 at the Medical University of Innsbruck, Austria. Cases were divided into two groups depending on the presence or absence of lymphatic CoNV (podoplanin staining). Follow-up was 2 years or until graft failure. Outcome parameters included the risk of graft failure and leakage patterns in a subgroup with preoperative indocyanine green (ICG) angiography.

Results: Of 17 included patients, lymphatic CoNV was identified in the excised corneal buttons of 10 cases (group 1). Seven cases stained only for haematic CoNV (group 2). Group 1 had a shorter age of CoNV (0.6±0.4 vs 2.3±0.8 years, p<0.001) and a higher rate of graft failure (6/10 vs 0/7, p=0.005). Lymphatic CoNV was only present in the age of CoNV less than 12 months. ICG leakage was associated with a younger age of CoNV (p=0.0338), corresponding to the presence of lymphatic CoNV at a younger age of CoNV.

Conclusion: Lymphatic CoNV in haemvascularised corneal stromal beds increases the risk of graft failure within 2 years. Lymphatic CoNV regression occurs within the first year of an inciting event. This time period or the presence of ICG dye leakage indicates a very high risk for corneal transplantation.