AIM: To investigate the changes in levels of the lactate dehydrogenase (LDH) enzyme in corneal edema after cataract surgery with trans-corneal oxygenation therapy. METHODS: This pre-post design study design conducted on 15 patients with corneal edema after cataract surgery and receiving trans-corneal oxygenation therapy. Tear sample (using Schirmer paper, from the inferior fornix of the conjunctiva) was carried out prior to trans-corneal oxygenation therapy, on the day 2 (D2) and day 5 (D5) postoperatively before and after trans-corneal oxygenation therapy. Visual acuity [VA (LogMAR)], corneal endothelial density, central corneal thickness (CCT), and coefficient of variation corneal endothelial (CoV) were recorded. The value of LDH was measured using ELISA. The difference in mean LDH value before and after trans-corneal oxygenation therapy, between two groups were analyzed using Wilcoxon signed rank test. RESULTS: There was a decrease in LDH tear concentration at D2 (pre vs post: 1127.54±497.09 vs 696.91±489.49; P=0.002) and D5 (pre vs post: 1064.17±677.77 vs 780.28±428.95; P=0.027) after trans-corneal oxygenation therapy as well as decrease in LDH concentration on the D2 compared to D5 (P=0.041). The mean CCT was decreased significantly after the administration of trans-corneal oxygenation (pre vs post: 632.10±25.66 vs 563.90±51.54; P=0.005). The mean VA and CoV increased significantly after the administration of trans-corneal oxygenation (P=0.001 and P=0.028, respectively). However, there was no difference in mean of corneal endothelial density (P=0.814). CONCLUSION: Trans-corneal oxygenation therapy is associated with significant decrease of tears LDH levels in post cataract surgery with corneal edema. It is accompanied by clinical improvement such as significant reduction of CCT.