Lumière diffractée et sensibilité à l’éblouissement après PKR et LASIK guidés par front d’onde

Optical quality and intraocular scattering after femtosecond laser small incision lenticule extraction

PURPOSE

To investigate objective optical quality and changes in light scatter after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction.

METHODS

Prospective clinical study of 66 eyes of 66 patients (23 males, 43 females) with a mean age of 28.67 ± 6.62 years, mean spherical refraction of -6.06 ± 1.57 diopters, and mean cylindrical refraction of -0.68 ± 0.46 diopters. Every patient had a 3-month follow-up after a standard SMILE procedure. An optical quality analysis system was used to measure modulation transfer function cutoff frequency (MTFcutoff), Strehl2D ratio, and objective scatter index (OSI).

RESULTS

At 3 months postoperatively, mean spherical equivalent was 0.03 ± 0.24 diopters and corrected distance visual acuities of all patients were equal to or better than preoperative values, with a mean safety index of 1.12 ± 0.17 (range: 0.80 to 1.50) and mean efficacy index of 1.18 ± 0.21 (range: 0.80 to 1.50). Mean OSI increased from 0.75 preoperatively to 1.09 at 20 days postoperatively (P < .05), and gradually declined to 0.94 at 40 days and 0.82 at 3 months postoperatively (P > .05). MTFcutoff and Strehl2D ratio did not change significantly compared with preoperative values (P > .05). Multiple linear regression analysis revealed that preoperative OSI was significantly correlated with optical quality at 3 months. Patients with less preoperative OSI tended to acquire higher MTFcutoff (b = -8.61) and lower OSI (b = 0.65) (P < .05).

CONCLUSIONS

SMILE had little impact on retinal image quality after myopia correction. Postoperative OSI showed a temporary increase and then returned to normal.