Abstract
Purpose:
To evaluate the role of epithelial remodeling on Femto-LASIK flap architecture and refractive regression after flap creation with IntraLASE FS60 in one eye and WaveLight FS200 Femtosecond Laser in the fellow eye using a Spectral Domain OCT.
Methods:
36 myopic eyes of 18 patients underwent femtosecond laser LASIK with ALLEGRETTO WAVE® Eye-Q Excimer Laser. The randomization was obtained for IntraLASE FS60 in one eye and WaveLight FS200 Femtosecond Laser in the contralateral eye. All flaps were created by a single surgeon and an intended flap thickness of 110μm. Anterior Segment Spectral- domain OCT-Optovue RTVue-100 (6 mm Pachymetry+Cpwr scans) was used to evaluate the epithelial thickness profile, Femto-LASIK flap and corneal architecture preoperatively, 1 week and 3 months postoperatively. Segmentation of the images was performed in 8 meridians for total thickness, flap thickness and epithelial-Bowman's transition. The average thickness of the central (2mm), superior and inferior zones (2-5mm) was calculated. Manifest and wavefront refractions were performed at 1 week, 1 month and 3 months postoperatively.
Results:
Spherical equivalent (SE) was -3.2±2.11D preoperatively, -0.28±0.42D at 1 week and 0.38±0.51D at 3 months postoperatively in the IL group and -3.25±1.83, -0.08±0.48D and 0.27±0.51D in the FS 200 group, respectively. UCVA was 20/20 or better in 100% of eyes in both groups. Significant epithelial thickening was observed in both groups centrally and inferiorly at 3 months postoperatively (p=0.033 and p=0.007, respectively). Three dimensional flap thickness analysis revealed thickening of the flap at 3 months. Mean flap thickness in the FS200 group was 106.78±3.93 centrally, 108.0±5.24 inferiorly and 106.11±4.88 superiorly at 1 week postop and 109.78±5.63, 111.33±8.44 and 107.67±5.74 at 3 months respectively. Mean flap thickness in the IL60 group was 107.44±4.03 centrally, 110.11±5.11 inferiorly and 109.56±4.88 superiorly at 1 week postop and 115.11±4.37, 116.56±7.62 and 114.44±6.50 at 3 months respectively.
Conclusions:
Significant epithelial and Femto-LASIK flap thickening were observed at 3 months after Femto-LASIK for myopia along with mild myopic regression. Epithelial remodeling may play a role on early refractive instability after LASIK.
Keywords: 482 cornea: epithelium •
683 refractive surgery: LASIK •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)