JKOS Journal of the Korean Ophthalmological Society J Korean Ophthalmol Soc 0378-6471 2092-9374 The Korean Society for Quality Management 10.3341/jkos.2015.56.7.992 jkos-56-992 Original Article Surface Ablation with 0.02% Mitomycin C for Retreatment after LASIK and LASEK KimKang Yoon M.D 1 KimHong Seok M.D 2 JungJi Won M.D 1 LeeHyung Keun M.D, PhD 1 SeoKyoung Yul M.D, PhD 1 KimEung Kweon M.D, PhD 1 KimTae Im M.D, PhD 1 The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea Siloam Eye Hospital, Seoul, Korea Address reprint requests to Tae Im Kim MD, PhD Department of Ophthalmology, Severance Hospital, #50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea Tel: 82-2-2228-3570, Fax: 82-2-312-0541 E-mail: TIKIM@yuhs.ac 08 2015 27 8 2015 56 7 992 997 29 01 2015 26 02 2015 04 06 2015 Copyright © 2015 Korean Ophthalmological Society 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose:

To evaluate the efficacy and safety of surface ablation with mitomycin C (MMC) for the retreatment of refractive errors following laser-assisted in-situ keratomileusis (LASIK) and laser-assisted sub-epithelial keratectomy (LASEK).

 Methods:

In this retrospective clinical study conducted at a single center, we evaluated 23 eyes that received surface ablation with MMC (0.02%, 20 seconds) between 2009 and 2013 for the treatment of residual refractive errors following myopic LASIK and LASEK. All eyes were evaluated for corneal thickness, initial refractive error, time interval to retreatment, amount of retreat-ment, duration of postoperative topical steroids use as well as uncorrected vision, spherical equivalent and corneal haziness pre-operatively and 1, 3, 6 and 12 months postoperatively.

 Results:

Initially corrected myopia in the LASIK group was -6.47 ± 2.17 D and -5.68 ± 2.51 D in the LASEK group. Mean time be-tween initial and retreatment by surface ablation was 11.88 ± 5.59 months for LASIK and 14.07 ± 10.10 for LASEK. Retreat amount was 1.49 ± 0.36 D after LASIK and -1.65 ± 0.41 D after LASEK. At postoperative 12 months, uncorrected visions were -0.061 ± 0.886 (log MAR) in the LASIK group and -0.004 ± 0.745 (log MAR) in the LASEK group and spherical equivalents were -0.55 ± 0.56 D in the LASIK group and 0.36 ± 0.33 D in the LASEK group. Postoperative hazes developed in 1 of 8 LASIK eyes and 3 of 15 LASEK eyes which resolved with application of topical steroid for 2-3 months postoperatively.

 Conclusions:

Surface ablation with 0.02% MMC is safe and highly effective for treating myopic regression following LASIK or LASEK. Application of 0.02% MMC for 20 seconds was effective in preventing postoperative haze formation and maintaining stable vision and spherical equivalent at 12 months after retreatment.

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Patient demographics

Retreatment after LASIK Retreatment after LASEK p-value
Number of eyes 8 15
Age (years) 27.0 ± 3.7 (24-35) 30.5 ± 6.5 (21-43) 0.24
Mean interval (months)∗ 11.88 ± 5.59 (5-19) 14.07 ± 10.10 (5-34) 0.93
Initial corneal thickness (μ m) 555.25 ± 22.28 528.47 ± 18.34 0.01†
SE at initial (diopter) -6.47 ± 2.17 -5.68 ± 2.51 0.47
Ablated amount during LASIK/LASEK (μ m) 92.13 ± 26.05 89.47 ± 42.89 0.98
SE before retreatment (diopter) -1.49 ± 0.36 -1.65 ± 0.41 0.43
Ablated amount during retreatment (μ m) 25.50 ± 8.94 22.33 ± 5.04 0.51

Values are presented as mean ± SD and range.

LASIK = laser-assisted in-situ keratomileusis; LASEK = laser-assisted sub-epithelial keratectomy; SE = spherical equivalent.

Mean time interval between initial LASIK/LASEK and enhancement operation; † Statistically significant difference ( p < 0.05).

Visual acuity and spherical equivalent before and after retreatment

Retreatment after LASIK Retreatment after LASEK p-value
Preop UCVA 0.319 ± 0.853 0.276 ± 0.921 0.39
POD 1 month UCVA 0.097 ± 0.699 0.086 ± 0.553 0.98
POD 1 month SE -0.77 ± 0.93 -0.26 ± 0.62 0.15
POD 3 months UCVA 0.009 ± 0.721 0.022 ± 0.770 0.98
POD 3 months SE -0.63 ± 0.90 -0.33 ± 0.63 0.55
POD 6 months UCVA -0.037 ± 0.886 -0.004 ± 0.745 0.29
POD 6 months SE -0.34 ± 0.52 -0.59 ± 0.54 0.29
POD 12 months UCVA -0.061 ± 0.886 -0.004 ± 0.745 0.13
POD 12 months SE -0.55 ± 0.56 -0.36 ± 0.33 0.33
Cases of haze 1 eye (12.5%) 3 eyes (20%)
Steroid use (months) 3.88 ± 0.83 2.33 ± 0.98 0.002∗

Values are presented as mean ± SD unless otherwise indicated. UCVA presented in log MAR scale.

LASIK = laser-assisted in-situ keratomileusis; LASEK = laser-assisted sub-epithelial keratectomy; Preop = preoperation; UCVA = uncorrected visual acuity; POD = postoperative day; SE = spherical equivalent.

Statistically significant difference ( p < 0.05).