Sheldon Herzig MD, FRCSC Herzig Eye Institute Toronto, Ontario

Transcription

1 Sheldon Herzig MD, FRCSC Herzig Eye Institute Toronto, Ontario

2 Clinical Visual quality Improved safety Financial Increase LVC volume Personal

3 Peer-reviewed papers Conversations with users Observe experienced surgeon

4 Reduce prolonged dry eye Better corneal biomechanics Flap issues Reduce PRKs Have another treatment modality for higher risk patients Dry eyes Thin corneas with normal imaging

5 Achieved SEQ [D] % Of eyes Excellent predictablity, results very close to target refraction, even for high myopic corrections Refractive outcomes within ±0.5 D for 97% of eyes eyes 3 months postop overcorrected 90% 80% 70% 269 eyes 3 months postop 81% ± 0.50 D: 97% ± 1.00 D: 100% -6 60% -5-4 undercorrected 50% 40% 30% Attempetd SEQ [D] mean: / range: -1.0 to % 10% 0% 0% 0% 0% 1% < to to % to to to % to % 0% 0% 0% to to to 2.00 Postoperative Spherical Equivalent Refraction > * * Controlled multicenter study, 3 study sites

6 Efficacy, safety, predictability, contrast sensitivity, and aberrations after femtosecond laser lenticule extraction Anders H. Vestergaard, Jakob Grauslund, Anders R. Ivarsen, Jesper Ø. Hjortdal. JCRS 40(3):

7 1 eye done with SMILE, 1 with LASIK Same results from 1-3 D LASIK results dropped off from 6-8 D SMILE results were the same at 1-3D and 6-8D

8 LASIK needs longer Rx time for high myopes Corneal surface is exposed and drying Environmental factors Temp. and Humidity SMILE Rx time same for all powers Done in a tightly closed system Not affected by environment or corneal drying

9 Dry eye is related to loss of corneal sensation which is more prolonged after LASIK than SMILE The corneal nerve plexus is mainly in Bowmans and subepithelial Both PRK and LASIK are more destructive to the corneal nerves Long-term Effects of LASIK on Corneal Innervation and Tear Neuropeptides and the Associations With Dry Eye Cecilia Chao, PhD; Blanka Golebiowski, PhD; Xiangtian Zhao, PhD; Shihao Chen, OD; Shi Zhou, MS; Fiona Stapleton, PhD

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11 Personal observation that Asians, especially women have higher incidence of prolonged dry eye after LASIK Chronic dry eye persisting more than 6 mos after LASIK occurred in 28% of Asians and 5% of Caucasians Albietz JM, et al. Dry eye after LASIK: Comparison of outcomes for Asian and Caucasian eyes. Clinical and Experimental Optometry, 88(2),

12 Wilson SE. Laser in situ keratomileusis-induced (presumed) neurotrophic epitheliopathy. Ophthalmology. 2001;108: Savini G, Barboni P, Zanini M, Tseng SC. Ocular surface changes in laser in situ keratomileusis-induced neurotrophic epitheliopathy. J Refract Surg. 2004;20: Solomon R, Donnenfeld ED, Perry HD. The effects of LASIK on the ocular surface. Ocul Surf. 2004;2: Shtein RM. Post-LASIK dry eye. Expert Rev Ophthalmol. 2011;6: Reinstein DZ, Archer TJ, Gobbe M, Bartoli E. Corneal Sensation after Small Incision Lenticule Extraction (SMILE). J Cataract Refract Surg [In Press]. Xu Y, Yang Y. Dry eye after small incision lenticule extraction and LASIK for myopia. J Refract Surg. 2014;30:

13 Vestergaard AH, Grønbech KT, Grauslund J, Ivarsen AR, HjortdalJØ. Subbasal nerve morphology, corneal sensation, and tear film evaluation after refractive femtosecond laser lenticule extraction. Graefes Arch Clin Exp Ophthalmol Nov;251(11): Li M1, Zhao J, Shen Y, Li T, He L, Xu H, Yu Y, Zhou X.: Comparison of dry eye and corneal sensitivity between small incision lenticule extraction and femtosecond LASIK for myopia. PLoS One Oct 29;8(10):e77797.

14 The side-cut in LASIK is what weakens the cornea the most Knox Cartwright NE, Tyrer JR, Jaycock PD, Marshall J. Effects of Variation in Depth and Side Cut Angulations in LASIK and Thin-flap LASIK Using a Femtosecond Laser: A Biomechanical Study. J Refract Surg. 2012;28:

15 Anterior 30% of the cornea is the strongest Posterior 60% of the cornea is at least 50% weaker Reinstein DZ, Archer TJ, Randleman JB. Mathematical Model to Compare the Relative Tensile Strength of the Cornea After PRK, LASIK, and Small Incision Lenticule Extraction. J Refract Surg. 2013;29:

16 SMILE corneal strength = Cap thickness+ RST (250m) LASIK corneal strength = RST only (300m) This allows for more safe tissue removal with SMILE which allows for a larger OZ

17 Knox Cartwright NE, Tyrer JR, Jaycock PD, Marshall J. Effects of Variation in Depth and Side Cut Angulations in LASIK and Thin-flap LASIK Using a Femtosecond Laser: A Biomechanical Study. J Refract Surg. 2012;28: Medeiros FW, Sinha-Roy A, Alves MR, Dupps WJ, Jr. Biomechanical corneal changes induced by different flap thickness created by femtosecond laser. Clinics (Sao Paulo). 2011;66: Randleman JB, Dawson DG, Grossniklaus HE, McCarey BE, Edelhauser HF. Depth-dependent cohesive tensile strength in human donor corneas: implications for refractive surgery. J Refract Surg. 2008;24:S85-89.

18 Reinstein DZ, Archer TJ, Randleman JB. Mathematical Model to Compare the Relative Tensile Strength of the Cornea After PRK, LASIK, and Small Incision Lenticule Extraction. J Refract Surg. 2013;29: Wang D, Liu M, Chen Y, Zhang X, Xu Y, Wang J, To CH, Liu Q. Differences in the Corneal Biomechanical Changes After SMILE and LASIK. J Refract Surg. 2014;30: Wu D, Wang Y, Zhang L, Wei S, Tang X. Corneal biomechanical effects: Small-incision lenticule extraction versus femtosecond laser-assisted laser in situ keratomileusis. J Cataract Refract Surg

19 SMILE can t as yet do a WFO or WFG Rx SMILE will cause less SA because of larger OZ May have less HOAs because Rx not exposed to environment Komiya K, et al. Comparison of visual acuity, higher-order aberrations and corneal asphericity after lenticule extraction and wavefront-guided laser-assisted in situ keratomileusis for myopia. Br J Ophthalmol 2013; 97:

20 Gain competitive advantage Referral sources Word of mouth Develop new public interest Reduce PRKs

21 SMILE outcomes were comparable to LASIK and possibly better for high myopes I felt it was safer Less dry eye Stronger corneal biomechanics Less risk of ectasia Able to treat thinner corneas avoiding PRK It may induce less HOAs It may provide a competitive advantage

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