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Dan Z Reinstein, Kishore Pradhan, Glenn Ian Carp, Timothy J Archer, Marine Gobbe, Raynan Khan; Preliminary evaluation of hyperopic SMILE in amblyopic eyes. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3928.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate optical quality and centration outcome measures of small incision lenticule extraction (SMILE) for hyperopia.
This was a prospective ethical committee approved study for eyes with hyperopic astigmatism treated by SMILE using the VisuMax femtosecond laser (Carl Zeiss Meditec). Study inclusion criteria were a maximum intended sphere up to +7 D with astigmatism up to 6 D, age ≥21 years, CDVA 20/100 or worse. Optical zone was centered on the corneal vertex and fixed at 6.3 mm with a 2 mm transition zone, 30 μm minimum lenticule thickness, and 120 μm cap thickness. Retinoscopic refraction and Atlas topography were obtained before and 1 month after surgery. Twenty eyes were included and 1 month data were available in 11 eyes at the time of writing. Refractive predictability, optical zone centration, achieved optical zone diameter (assessed by tangential curvature difference maps to the mid-peripheral power inflection point), and change in corneal spherical aberration (6 mm) were analyzed. MEL80 corneal vertex centered LASIK eyes matched for sphere and cylinder (±0.50 D) were randomly mined from our database to make 2 control groups: optical zone 6.5 mm or 7 mm (both transition 2 mm).
Mean SEQ was +4.68±1.30 D (+3.00 to +6.42 D). Mean refractive astigmatism was 1.09±0.65 D (0.50 to 2.75 D). Mean postop SEQ was +0.10±0.91 D (-1.16 to +1.50 D); 27% ±0.50 D and 82% ±1.00 D. Mean spherical aberration change was -0.49 μm in the 6.3 mm SMILE group, found to be equivalent to the 7 mm LASIK group (-0.47 μm, p=0.916), but less than the 6.5 mm LASIK group (-0.79 μm, p=0.002). Mean optical zone offset was equal for all groups (p>0.73); 0.30±0.18 mm in the 6.3 mm SMILE group, 0.34±0.26 mm in the 7 mm LASIK group, and 0.29±0.15 mm in the 6.5 mm LASIK group. Mean achieved optical zone diameter was 5.55±0.35 mm in the 6.3 mm SMILE group; larger than the 6.5 mm LASIK group (4.65±0.18 mm, p<0.001) and the 7 mm LASIK group (4.93±0.32 mm, p<0.001).
Optical zone centration was equivalent between vertex centered hyperopic SMILE and LASIK. Less spherical aberration was induced by 6.3 mm SMILE than 6.5 mm LASIK and was equivalent to 7 mm LASIK. Achieved topographic optical zone diameter was larger for 6.3 mm SMILE than 6.5 and 7 mm LASIK. Refraction change by retinoscopy appeared relatively accurate although longer term sighted eye studies will be required to refine nomograms and balance these with observed regression.
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