Clinical Evaluation of Corneal Epithelialization after Photorefractive Keratectomy in Patients Treated with Polydeoxyribonucleotide (PDRN) Eye Drops: A Randomized, Double-blind, Placebo-controlled Trial

Purpose The effect of polydeoxyribonucleotide (PDRN) eye drops vs placebo on corneal epithelial healing after photorefractive keratectomy (PRK) for correction of myopic and myopic-astigmatic defects was evaluated in a randomized, double-blind clinical trial. Primary endpoint for efficacy was the evolution of corneal re-epithelialization. Secondary endpoint was the evaluation of PDRN eye drops tolerability. Methods Sixty eyes were enrolled in the study, randomly allocated into standard therapy plus placebo eye drops (30 eyes), or standard therapy plus PDRN eye drops (30 eyes). Checks were carried out preoperatively and at days 1, 2, 3, and 7 of the follow-up. Six eyes dropped out (four in PDRN group, two in placebo group) for reasons unrelated to the study. Results On day 2, the disepithelialized area was 8.4 mm 2 ± 9.2 (mean ± SD) in controls and 6.0 mm 2 ± 6.8 in PDRN group. On day 3 a complete corneal re-epithelialization was found in 20 out of 26 (77%) eyes of PDRN group and in 17 out of 28 (61%) eyes of placebo group (p<0.05 in percentage terms). On day 7 of follow-up, all eyes appeared to be completely re-epithelialized. The mean score of corneal evaluation on day 3 was 2.9 in PDRN group and 3.75 in control group (p<0.05 between groups). No adverse events occurred during the study. Conclusions The data of the study have shown that after PRK, PDRN stimulates corneal epithelium regeneration. PDRN eye drops administration four times a day is well tolerated by patients during the re-epithelialization stage. A much larger clinical study should be performed in order to prove the results obtained in this pilot study.