Mitomycin C aqueous humor concentration after photorefractive keratectomy: an experimental study

PURPOSE. To evaluate mitomycin C (MMC) aqueous humor concentration after photorefractive keratectomy (PRK). METHODS. In this experimental study, twenty-four eyes of 12 male pigmented rabbits were divided into 4 groups and studied at the Institute of Vision and Optics, Department of Medicine, University of Crete, Greece. Eyes in groups 1 and 2 underwent PRK to correct -5 diopters (D) in a 6-mm optical zone, while sponges soaked with 0.02% MMC were applied on the exposed corneal stroma for 60 and 120 seconds, respectively. Similarly, eyes in groups 3 and 4 underwent PRK to correct -10 D in a 6-mm optical zone, while sponges soaked with 0.02% MMC were applied on the exposed corneal stroma for 60 and 120 seconds, respectively. Aqueous humor was extracted from all rabbit eyes 10 minutes after MMC application and high-performance liquid chromatography was performed immediately to detect and quantify MMC levels. RESULTS. The mean aqueous humor concentration of MMC was 0.23+/-0.03 mu g/mL, 0.39+/-0.05 mu g/mL, 0.28+/-0.04 mu g/mL, and 0.52+/-0.16 mu g/mL in groups 1, 2, 3, and 4, respectively. The effect of application time and correction on aqueous humor MMC concentration was significant (p<0.0001 and p=0.019), while the exposure time had a greater impact on aqueous humor MMC concentration when compared with the attempted correction. CONCLUSIONS. Both exposure time of MMC on the corneal stroma and the attempted correction was correlated with MMC aqueous humor concentrations. (Eur J Ophthalmol 2009; 19: 738-42)