Abstract
Purpose :
To evaluate visual and refractive outcomes, optical quality and centration of small incision lenticule extraction (SMILE) for hyperopia.
Methods :
Prospective study of vertex-centered hyperopic SMILE using the VisuMax femtosecond laser (Carl Zeiss Meditec). Inclusion criteria were intended sphere ≤+7.00 D, astigmatism ≤6.00 D, and age ≥21 years. Lenticule parameters were 6.3-6.5 mm diameter, 2 mm transition zone, 30 μm minimum thickness, and 120 μm cap thickness. The study was divided into phases based on CDVA, starting with densely amblyopic eyes and progressing to sighted eyes. Manifest refraction and Atlas topography were obtained before and 3 months after surgery for 57 eyes. Optical zone centration, optical zone diameter (based on Atlas tangential curvature difference maps), and change in corneal spherical aberration were analyzed for all eyes and compared to MEL80 LASIK matched control groups for 6.5 mm and 7 mm optical zones (transition 2 mm). Visual and refractive outcomes were analyzed for eyes with CDVA 20/40 or better (sighted eyes, n=31). Refractive predictability was compared to a MEL80 LASIK matched control group.
Results :
Mean attempted SEQ was +5.63±0.90 D (+3.20 to +6.87 D). Mean astigmatism was 1.22±1.00 D (0.00 to 4.00 D). Mean optical zone offset was not different between SMILE and LASIK (p>0.77); 0.30±0.21 mm in SMILE and 0.32±0.20 mm in LASIK. Mean achieved optical zone diameter was 5.02±0.30 mm for 6.3 mm SMILE; larger than 6.5 mm LASIK (4.58±0.24 mm, p<0.001) and 7 mm LASIK (4.90±0.25 mm, p<0.05). Mean spherical aberration change was -0.53 μm in 6.3 mm SMILE, equivalent to 7 mm LASIK (-0.47 μm, p=0.916), but less than 6.5 mm LASIK (-0.76 μm, p<0.01). For the 31 sighted eyes (CDVA 20/40 or better), UDVA was 20/40 or better in 84% and 20/63 or better in 100% of eyes. Mean postop SEQ relative to the intended target was -0.04±0.79 D (-2.20 to +1.88 D), with 65% within ±0.50 D and 87% within ±1.00 D. No eyes lost 2 or more lines CDVA. Predictability was 53% within ±0.50 D for the LASIK control group.
Conclusions :
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. Refractive predictability of SMILE was similar or better than for LASIK.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.