Laser subepithelial keratomileusis Laser subepithelial keratomileusis (LASEK) retreatment surgery(LASEK) retreatment surgeryColm McAlinden,Colm McAlinden,1,21,2 Jonathan Moore, Jonathan Moore,2,32,3

11School of Biomedical Sciences, University of Ulster, UK;School of Biomedical Sciences, University of Ulster, UK;22Cathedral Eye Clinic, York Street, Belfast, UK;Cathedral Eye Clinic, York Street, Belfast, UK;

33Mater Hospital, Belfast Health and Social Care Trust, UK.Mater Hospital, Belfast Health and Social Care Trust, UK.

Funding from the Department for Employment and Learning (DEL), Belfast, UK.Funding from the Department for Employment and Learning (DEL), Belfast, UK.No author has a financial or proprietary interest in any material or method mentioned.No author has a financial or proprietary interest in any material or method mentioned.

BackgroundBackground Laser enhancement may be required when:Laser enhancement may be required when:

Suboptimal visual outcomeSuboptimal visual outcome1-31-3

OvercorrectionOvercorrection UndercorrectionUndercorrection Regression Regression

Due to a variety of factorsDue to a variety of factors4-64-6

Magnitude of refractive errorMagnitude of refractive error Variable corneal wound healingVariable corneal wound healing Compensatory epithelial hyperplasiaCompensatory epithelial hyperplasia Ablation algorithmAblation algorithm Nonaccurate nomogramsNonaccurate nomograms AgeAge

BackgroundBackground

LASEK enhancements are often performed LASEK enhancements are often performed with mitomycin C in order to reduce the risk with mitomycin C in order to reduce the risk of corneal hazeof corneal haze

AimsAims

The aim of this study is to investigate the The aim of this study is to investigate the outcomes of LASEK retreatment surgery outcomes of LASEK retreatment surgery without the use of MMC in terms of without the use of MMC in terms of predictability, safety, efficacy and stabilitypredictability, safety, efficacy and stability..

MethodsMethods Twenty two eyes of 15 patients (mean age 32 years; age range

21 to 56 years) underwent LASEK retreatment surgery following initial LASEK.

The LASEK retreatment procedure was identical in technique to the original LASEK surgery; 20% C2H5OH was instilled for 40 seconds, without the use of mitomycin C.

The mean pre-operative spherical and cylindrical refraction was -3.01 dioptres (range: +5.25 to -6.00) and -1.18 dioptres (range: +0.00 to -5.00) respectively.

The mean pre-retreatment spherical and cylindrical refraction was -0.47 dioptres (range: +1.50 to -1.75) and -0.47 dioptres (range: +0.00 to -1.25) respectively.

All treatments were wavefront guided using the VISX S4 Star excimer laser. All procedures were wavefront-guided using the VISX S4 Star excimer laser (CustomVue)

ResultsResults Six months post-retreatment, the mean spherical and Six months post-retreatment, the mean spherical and

cylindrical refraction was +0.03 dioptres (range: -0.25 to +0.50 cylindrical refraction was +0.03 dioptres (range: -0.25 to +0.50 dioptres) and -0.02 dioptres (range: +0.00 to -0.75 dioptres) dioptres) and -0.02 dioptres (range: +0.00 to -0.75 dioptres) respectively. respectively.

The mean UCVA and BCVA was 1.19±0.11 and 1.22±0.13 The mean UCVA and BCVA was 1.19±0.11 and 1.22±0.13 respectively. respectively.

No intraoperative complications were encountered.No intraoperative complications were encountered. Grade 1 haze occurred in four eyes which subsided in all cases Grade 1 haze occurred in four eyes which subsided in all cases

by eight weeks with continued topical steroid treatment.by eight weeks with continued topical steroid treatment.

ConclusionConclusion LASEK retreatments without the use of mitomycin C provided LASEK retreatments without the use of mitomycin C provided

good visual and refractive outcomes. good visual and refractive outcomes. With the known and unknown potential side-effects of With the known and unknown potential side-effects of

mitomycin C, LASEK retreatments may be safe and effective mitomycin C, LASEK retreatments may be safe and effective without the use of mitomycin C. without the use of mitomycin C.

Long term studies on the use of mitomycin C with Long term studies on the use of mitomycin C with retreatment surgery over a large refractive range is retreatment surgery over a large refractive range is necessary.necessary.

ReferencesReferences1.1. Huang D, Stulting RD, Carr JD, Huang D, Stulting RD, Carr JD, et al.et al. Multiple regression and Multiple regression and

vector analyses of laser in situ keratomileusis for myopia and vector analyses of laser in situ keratomileusis for myopia and astigmatism. astigmatism. J Refract Surg.J Refract Surg. 1999; 15: 538-549. 1999; 15: 538-549.

2.2. Ditzen K, Handzel A, Pieger S. Laser in situ keratomileusis Ditzen K, Handzel A, Pieger S. Laser in situ keratomileusis nomogram development. nomogram development. J Refract Surg.J Refract Surg. 1999; 15(suppl): S197- 1999; 15(suppl): S197-S201.S201.

3.3. Roberts C. The cornea is not a piece of plastic. Roberts C. The cornea is not a piece of plastic. J Refract Surg.J Refract Surg. 2000; 16: 407-413.2000; 16: 407-413.

4.4. Mohan RR, Hutcheon AE, Choi R Mohan RR, Hutcheon AE, Choi R et al.et al. Apoptosis, necrosis, Apoptosis, necrosis, proliferation, and myofibroblast generation in the stroma proliferation, and myofibroblast generation in the stroma following LASIK and PRK. following LASIK and PRK. Exp Eye Res.Exp Eye Res. 2003; 76: 71-87. 2003; 76: 71-87.

5.5. Helena MC, Baerveldt F, Kim WJ et al. Keratocyte apoptosis Helena MC, Baerveldt F, Kim WJ et al. Keratocyte apoptosis after corneal surgery. after corneal surgery. Invest Ophthalmol Vis Sci.Invest Ophthalmol Vis Sci. 1998; 39: 276– 1998; 39: 276–283.283.

6.6. Ibrahim O. Laser in situ keratomileusis for hyperopia and Ibrahim O. Laser in situ keratomileusis for hyperopia and hyperopic astigmatism. hyperopic astigmatism. J Refract Surg.J Refract Surg. 1998; 14(suppl): S179- 1998; 14(suppl): S179-S182.S182.