Comparison of LASIK and Mitomycin-C Assisted LASEK for Correction of Refractive Errors After Cataract Surgery Dr. Nitin Balakrishnan, Crystal Vision Laser Centre, Mumbai, India. Dr. Shilpa Kodkany, Dr. Kodkany’s Eye Care Centre, Belgaum, India.. No author has any financial or proprietary interest in any materials or methods mentioned

PURPOSE To compare the results of Laser in situ keratomileusis (LASIK) & Mitomycin C assisted, Laser subepithelial keratomileusis (LASEK), to correct residual refractive errors following cataract surgery. DESIGN Dual centre, comparative, retrospective study.

METHODS Nineteen Patients (20 eyes) - 10 males & 9 females had LASIK. Nineteen Patients (19 eyes) - 8 males & 11 females had LASEK. Patient’s Age varied from 51 to 66 years. Interval between Cataract Surgery and Refractive procedure – 3 to 36 months(mean 14 months). All Patients had Phakoemulsification with In the Bag IOL implants. Pre-op Spherical Equivalent Refraction (SEQ) - + 4 to – 5 Diopters..

METHODS Ablated bed treated with 0.02% Mitomycin C for 90 seconds LASEK performed with 20% alcohol, for Mechanical Epithelial Debridement. Ablated bed treated with 0.02% Mitomycin C for 90 seconds LASIK flap made with Moria MII microkeratome, with a thickness of 130 or 90 microns. Wavelight Allegreto eximer laser was used for all patients. With repetition rate of 200 Hz & optical zone of 6 or 6.5mm. Eyes with tracking difficulties were excluded. Uncorrected Visual Acuity (UCVA),Best Spectacle-corrected Visual Acuity(BSCVA), percentage of eyes within Half diopter (D) of targeted refraction, targeted v/s achieved spherical equivalent correction and gain/ loss in Snellen’s lines were compared between the two groups. Length of follow up - 6 months

RESULTS - UCVA Percentage of eyes with UCVA ≥ 20/20 Postoperative period (months) Mean UCVA better in the LASIK group from 1 – 4 months No significant difference in mean UCVA at 6 months

RESULTS - BSCVA Percentage of eyes with BSCVA ≥ 20/20 Postoperative period (months) Mean BSCVA better in the LASIK group from 1 to 3 months No significant difference in mean BSCVA from 4 to 6 months

RESULTS - Post op Spherical Equivalent Refraction - 6 months Percentage of eyes Post op Spherical Equivalent Refraction in D

RESULTS - Percentage of eyes within ± 0.5D of Targeted Refraction

RESULTS - Targeted v/s Achieved Spherical Equivalent Refraction(LASIK) Group 20 eyes Targeted

Targeted v/s Achieved Spherical Equivalent Refraction(LASEK) Group 19 eyes

RESULTS - CHANGE IN SNELLEN’S LINES OF BCVA Percentage of eyes No eyes lost 2 or more Snellen’s lines of BCVA 6 eyes gained 1 Snellen’s line of BCVA in Both groups 2 eyes gained 2 Snellen’s lines of BCVA in LASIK group v/s 1 eye in LASEK group

CONCLUSIONS Both Mitomycin C assisted LASEK and LASIK effective in correcting post Cataract residual refractive errors. Short term superiority of LASIK over LASEK in the immediate post-op period. Equally good refractive correction at 6 months Gain in Snellen’s lines in BCVA, almost equal in both groups. Subepithelial Haze in LASEK group significantly less due to Mitomycin C , which decreased from Grade I + in first 2 months to < grade 0.5 at 6 months. Longer term studies required to determine refractive stability of the two procedures. REFERENCES 1.Ahn CS, et al. Initial results of PRK & LASIK performed by a single surgeon. J Cat Ref Surg 1999;25:1048-1055 2.Steinert RF, et al. Surgical correction of moderate myopia. II, PRK & LASIK are the treatments of choice. Surv Ophthal 1998;43:157-179 3.Ayala MJ, et al. LASIK to correct residual myopia after cataract surgery. J Refract Surg 2001; 17: 12-16 4.Sanchez-Galeana CA, et al. LASIK & PRK for residual ref error after phakic IOL implantation. J Refract Surg 2001;17:299-304 5.Guell JL, et al. LASIK for correction of residual ref errors from previous surgical procedures. Ophthalmic Surg Lasers 1999;30:341-349 6. Artola A, et al. PRK for residual myopia after cataract surgery. J Cat Ref Surg 1999;25:1456-1460 7.El Danasoury MA, et al. Comparison of PRK with LASIK in correcting low myopia: a randomised study. Ophthalmology 1999;106 :411-420 8.El-Maghraby A, et al. Randomised bilateral comparison of LASIK and PRKfor 2.5 to 8 D of myopia. 1999;106:447-457