Effect of intraoperative mitomycin C application at different concentrations on corneal densitometry after SmartSurf transepithelial photorefractive keratectomy.

Purpose: This study aimed to investigate corneal densitometry (CD), visual, and refractive outcomes after transepithelial photorefractive keratectomy (TPRK) using smart pulse technology (SPT), known as the SmartSurface procedure, in patients treated with or without mitomycin C (MMC) at concentrations of 0.01% and 0.02%.

Methods: This retrospective study analyzed 138 eyes of 138 patients who underwent SmartSurface surgery and were categorized into three groups based on intraoperative MMC concentration: the MMC group (0.02% MMC), the MMC group (0.01% MMC), and the Control group (no MMC), with 46 eyes per group. Corneal haze, uncorrected distance visual acuity (UDVA), and spherical equivalent (SE) were assessed preoperatively and at 2 weeks, 1 month, and 3 months postoperatively. Corneal densitometry was performed across different concentric radial zones (0–2, 2–6, and 6–10 mm annulus) and layers (anterior, central, posterior, and total) using Scheimpflug imaging preoperatively and at the same postoperative time points.

Results: Three months after SmartSurface treatment, the incidence of haze was significantly lower in the MMC (6.52%) and MMC (4.35%) groups than in the Control group (15.22%) ( = 0.048 and  = 0.01, respectively). The MMC and MMC groups showed no significant differences in haze incidence ( = 0.244). Furthermore, no significant differences were observed in UDVA or SE among the three groups at any postoperative time point (all  > 0.05). In terms of corneal densitometry, three months after surgery, the central layer CD values in the 0–2 mm zone (MMC: 14.48 ± 1.21 GSU vs. MMC: 14.56 ± 1.01 GSU vs. Control: 15.23 ± 1.25 GSU) and the posterior layer CD values (MMC: 11.49 ± 0.70 GSU vs. MMC: 11.40 ± 0.70 GSU vs. Control: 11.96 ± 0.78 GSU) were significantly lower in both MMC groups compared to the Control group (all  < 0.05). Similarly, in the 2–6 mm zone, the posterior layer CD values (MMC: 10.41 ± 0.75 GSU vs. MMC: 10.38 ± 0.59 GSU vs. Control: 10.88 ± 0.71 GSU) and total layer CD values (MMC: 13.39 ± 0.54 GSU vs. MMC: 13.36 ± 0.49 GSU vs. Control: 13.65 ± 0.51 GSU) were significantly lower in both MMC groups than in the Control group (all  < 0.05). However, no significant differences in CD values were found between the MMC and MMC groups across any zone or layer (all  > 0.05).

Conclusion: Both 0.01% and 0.02% MMC are similarly effective in preventing haze and enhancing corneal clarity following SmartSurface surgery. However, given the unproven long-term safety of MMC, its use at a lower concentration is advisable to avert potential complications.