Comparison of Tear Fluid Vascular Endothelial Growth Factor and Corneal Neovascularization between Bacterial and Fungal Corneal Ulcers

Purpose: Keratoplasty had a higher risk for rejection with the recipient's corneal neovascularization. Bacterial corneal ulcers have more neovascular area than fungal, however there was no comparison. This study compared tear fluid vascular endothelial growth factor (VEGF-A) and corneal neovascularization between bacterial and fungal corneal ulcers. Method: Corneal photographs and tear fluid of corneal ulcer patients at the first visit and after four weeks were studied. The corneal neovascularization area was measured using ImageJ® software. VEGF-A concentration was measured using enzyme-linked immunosorbent assay. Results: Twelve bacterial corneal ulcer patients and 10 fungal corneal ulcer patients showed a mean age of 37 years old. The most common bacteria was Pseudomonas aeruginosa and the most common fungi was Fusarium sp. The neovascular area was similar among the groups at the first visit (bacterial 10,3% (2,3-37,5) vs fungal 8,0% (3,7-22,8), p = 0,262), however, the bacterial group showed a larger neovascularization area at the fourth week (bacterial 21,6% (2,3-58,0) vs fungal 11,0% (5,4-22,5), which reached statistical significance after multivariate adjustment for potential confounders p=0,033). VEGF-A was similar at the first visit (bacterial 215,6 pg/ml (58,0-1111,6) vs fungal 339,3 pg/ml (22,7-1313,0), p=0,391) and the fourth week (bacterial 399,7 pg/ml (181,9-1496,3) vs fungal 743,8 pg/ml (78,7-1416,5), p=0,792). No significant correlation was found between VEGF-A and corneal neovascular area (first visit r -0,28, p=0,212, fourth week r -0,04 p=0,855). Conclusion: Bacterial keratitis showed larger corneal neovascularization than fungal keratitis. However, this study found no significant difference in tear fluid VEGF-A concentration between the two groups. No significant correlation was found between VEGF-A and corneal neovascular area. Further study is needed to measure additional mediators alongside VEGF-A to evaluate bacterial and fungal angiogenic factor.