Mitomycin C-assisted photorefractive keratectomy in high myopia: a long-term safety study.
OBJECTIVE
To evaluate the long-term corneal safety of topical mitomycin C (MMC) used during photorefractive keratectomy to prevent haze formation in highly myopic eyes.


METHODS
Twenty-eight patients with bilateral high myopia underwent photorefractive keratectomy. One eye was randomly assigned to intraoperative 0.02% MMC and the fellow eye to conventional treatment. Each eye was checked at baseline and at 5 years after surgery using in vivo corneal confocal microscopy.


RESULTS
At baseline, the endothelial cell density was 2970 ± 295 cells per square millimeter in the MMC-treated eyes and 2839 ± 323 cells per square millimeter in the control eyes. At 5 years, it was 2803 ± 307 and 2780 ± 264 cells per square millimeter, respectively (P = 0.27). The number of corneal nerve fibers was 3.9 ± 1.6 in the MMC-treated eyes and 4.4 ± 1.3 in the control eyes. At 5 years, it was 3.0 ± 1.6 and 2.7 ± 1.3, respectively (P = 0.15). The density of corneal nerves was 9600 ± 2915 μm/mm(2) in the MMC-treated eyes and 11,352 ± 3898 μm/mm(2) in the control eyes. At 5 years, the density was higher in the MMC-treated eyes (6790 ± 2447 μm/mm(2)) than in the control eyes (6024 ± 2977 μm/mm(2)) (P = 0.003). The number of nerve beadings at baseline was 12.9 ± 1.7/100 μm in the MMC-treated eyes and 12.3 ± 2.0/100 μm in the control eyes. At 5 years, it was 9.9 ± 2.6/100 and 9.4 ± 2.9/100 μm, respectively (P = 1.00). At 5 years, corneal nerve branching and tortuosity were similar in the 2 groups (P = 0.88 and 0.54, respectively). Epithelium thickness remained statistically unchanged (P = 0.69).


CONCLUSIONS
Intraoperative use of topical 0.02% MMC compared with standard treatment does not induce significant long-term corneal changes, as assessed by in vivo corneal confocal microscopy.
Department of Ophthalmology, University of Padua, Padua, Italy.
Catia
C
Gambato
Stefania
S
Miotto
Marta
M
Cortese
Alessandra
A
Ghirlando
Daniela
D
Lazzarini
Edoardo
E
Midena
D000287:Administration, Topical; D000328:Adult; D000477:Alkylating Agents / Q000008:administration & dosage*; D003131:Combined Modality Therapy; D003315:Cornea / Q000294:innervation; D055954:Corneal Endothelial Cell Loss / Q000473:pathology; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007430:Intraoperative Care; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D018613:Microscopy, Confocal; D016685:Mitomycin / Q000008:administration & dosage*; D047728:Myopia, Degenerative / Q000503:physiopathology / Q000601:surgery*; D009882:Ophthalmic Nerve / Q000473:pathology; D018903:Photorefractive Keratectomy / Q000379:methods*; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology
D000477:Alkylating Agents; D016685:Mitomycin