Official ESCRS | European Society of Cataract & Refractive Surgeons


Sub-Bowman flap 85 micron laser in situ keratomileusis: pilot study interim results

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Session Details

Session Title: LASIK & PRK II

Session Date/Time: Monday 16/09/2019 | 14:00-16:00

Paper Time: 14:00

Venue: Free Paper Forum: Podium 3

First Author: : B.Lin TAIWAN

Co Author(s): :    Y. Chuang   P. Lin                          

Abstract Details


To report on visual results, patient reported outcomes, flap thickness precision in eyes undergoing elliptical thin-flap LASIK (sub-Bowman keratomileusis; SBK) with a temporally hinged ,120° side-cut angles.


Universal eye center, Zhuang-Li, Taoyuan, Taiwan ROC.


A prospective pilot study to evaluate preoperative and postoperative tests included best spectacle-corrected visual acuity, uncorrected visual acuity (UCVA). Patients completed subjective questionnaires at each visit. Patients were evaluated before surgery and 1 day, 1 week and 2 weeks after surgery. In all cases customized WaveLight® EX500 Excimer Laser followed thin flap creation by OCT guided FEMTO LDV Z8 (Ziemer Ophthalmic Systems Port, Switzerland). A pain questionnaire was conducted at 1 day, 2 day and 1 week postoperatively. Target flap thickness varied 85μm in 10 eyes, 90 μm in 2 eyes, and 100 μm in 4 eyes.


The mean preoperative spherical refraction was diopters -6.27 D and the mean cylinder was 1.58 D for all eyes. At one day UCVA of 20/20 or better achieved in 10 eyes. Standardized flap parameters were programmed for each procedure. Intra-operative OCT (Ziemer Z8 LDV) for flap visualization. Heidelberg Optical Coherence Tomography used to measure the post-operative flap thickness. Achieved flap thickness were measured to be very close to intended flap thickness in all cases. All values within 95% confidence limit. All patients were highly satisfied with the procedure. No adverse events reported. No intra- or postoperative complications reported.


Thin-flap LASIK created by FEMTO LDV Z8 is considered to offer advantages of both surface and flap techniques which are biomechanical stability (more RSB thickness), comfortable, painless and leading to earlier visual recovery. Especially beneficial in patients with previous LASIK, and thin corneal patients with high myopia. The additional customization of the treatment can help the surgeon to visualize the epithelium and plan targeted Sub-bowman flaps of 80-90 µm effectively.

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