Refractive lenticule extraction flap and stromal bed morphology assessment with anterior segment optical coherence tomography

Abstract

Purpose: To evaluate the flap and stromal bed after refractive lenticule extraction using optical coherence tomography (OCT). Setting: Singapore National Eye Centre, Singapore. Design: Longitudinal case series. Methods: Horizontal scans (RTVue) were taken preoperatively and after refractive lenticule extraction. Two procedures were performed: femtosecond lenticule extraction and small-incision femtosecond lenticule extraction. Flap and bed thicknesses were measured at the center (0.0 mm) and 1.5 mm and 3.0 mm to either side. Results: At 1 week, the mean flap at 0.0 mm was borderline thicker (P=.056) and at +3.0 mm significantly thicker after femtosecond lenticule extraction than after small-incision femtosecond lenticule extraction (P=.003). The mean bed at 0.0 mm was thinner after femtosecond lenticule extraction (P=.03). The flap at -3.0 mm showed thinning between 1 week and 3 months after small-incision femtosecond lenticule extraction (P=.018). The flap at +3.0 mm thinned between 1 week and 1 month after femtosecond lenticule extraction (P=.009). After femtosecond lenticule extraction, there were increases in bed (P=.027) and total corneal (P=.013) thicknesses at 0.0 mm between 1 week and 3 months, remaining stable thereafter (3 months: P=.842 and P=.508, respectively). The mean spherical equivalent decreased and the uncorrected acuity improved after both procedures (P