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K. S. Bower, C. D. Coe, R. D. Stutzman, J. M. Burka, R. C. VanRoekel, D. A. Sediq, L. Peppers; US Army Surface Ablation Study: Comparison of PRK, MMC-PRK and LASEK in Moderate to High Myopia. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5325.
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© ARVO (1962-2015); The Authors (2016-present)
To compare visual outcomes, corneal haze, and complications following photorefractive keratectomy (PRK), PRK with mitomycin-C (MMC-PRK) and laser epithelial keratomileusis (LASEK) for moderate and high myopia.
Active Duty Army soldiers, age 21 or over with stable myopia between -4.00D and -10.00D manifest spherical equivalent (MSE) were randomized to treatment of their dominant eye with either MMC-PRK (0.1 mg/ml x 1 minute) or LASEK. The fellow eye received conventional PRK. All procedures were performed using the LADARVision 4000 with Jupiter 2 software version 5.11. Patients were examined at baseline and at 1, 3, 6, and 12 months. Examination included uncorrected visual acuity (UCVA), manifest refraction, best spectacle corrected visual acuity (BSCVA), slit lamp biomicroscopy, and corneal haze score.
56 subjects with at least 6 months follow-up were analyzed for this report: 32 LASEK (age 35.6 +/- 7.9 years) and 24 MMC-PRK (age 34.9 +/- 6.7 years). Pre-op MSE in the LASEK group was -6.08D +/- 1.36D in the LASEK eye (range -4.00 to -9.25D) and -6.19D +/- 1.43D in the PRK eye (-4.00 to -9.38D). In the MMC-PRK group, pre-op MSE was -6.23D +/- 1.41D (-4.00 to -9.38D) in the LASEK eye and -6.27D +/- 1.37D (-4.00 to -9.38D) in the PRK eye. Post-op MSE at the last visit (6 or 12 month) for MMC-PRK eyes was +0.05D (SE 0.16) and the fellow PRK eye was +0.05D (SE 0.12D). For LASEK treated eyes, post-op MSE was +0.06D (SE 0.11D) and -0.01D (SE 0.11D) for the fellow eye. Analysis of variance showed that the effect of treatment on refractive outcome was insignificant, F(3,108) = .73, p = .53. At 6 months post-op, 83% of MMC-PRK eyes (20/24) and 87.5% (21/24) of the fellow eye achieved an UCVA of 20/20 or better. 84% (27/32) of LASEK eyes and 93% of the fellow PRK eye achieved 20/20 or better. A chi-square test of independence was performed and the relationship between corneal haze and surgical treatment is not significant (X2 (2, N = 112) = 1.17, p =.558). A Mann-Whitney test, comparing either MMC-PRK or LASEK to fellow eye, showed there was no significant difference in incidence or severity of corneal haze (MMC-PRK v. PRK, n=48, p=.301; LASEK v. PRK, n=64, p=.644).
Preliminary results demonstrate no significant difference in refractive outcome, incidence of corneal haze, or adverse events across surgical procedures when compared to conventional PRK. Additional recruitment and follow-up are needed to establish procedure preference in terms of long-term safety and efficacy for the treatment of higher degrees of myopia.
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