3 Months Clinical Outcomes Following Lenticule Extraction Using A Femtosecond Laser Equipped With An Advanced Eye-Tracker In Cases With And Without Active Centration Compensation (Smartsight Classical Vs Smartsight Nova)

To assess the difference of KLEx treatments with vs without an active eyetracking compensation in terms of safety, efficacy, and refractive outcomes of myopic patients, both with and without astigmatism, employing a femtosecond laser system using a precise cyclotorsion compensation in all treatments.

Maria-Clara Arbelaez, MD, Muscat, Oman

In this retrospective, non-randomized cohort study, 220 eyes from 133 patients treated consecutively with SmartSight lenticule extraction were retrospectively analysed in two groups with and without active centration compensation (CenTrax feature). Group A (without CenTrax) 54 eyes of 29 patients and Group B (with CenTrax) 166 eyes of 85 patients. Over both groups the patients' mean age was 27 ± 6.5 years (range 18–46 years). At the three-month follow-up, visual acuity, SEQ, cylinder, safety index, and efficacy index were analysed individually for each group. All lenticule extraction treatments were performed using the SmartSight method with the SCHWIND ATOS femtosecond laser.

At 3 months after surgery, mean spherical equivalent SEQ in group A was -0.16 ± 0.33 D (range 0.00 to -1.50 D) and in group B was -0.01 ± 0.07 D (range 0.25 to -0.75 D). Astigmatism of less than ≤ 0.5 D was achieved in 96% of eyes in group A and in 99% in group B. The change in Snellen lines showed a gain of 1 or more lines in 7% in group A and in 17% in group B. There was no loss of 3.7% of 2 or more lines in group A and 0% in group B. Safety index was 0.99 and Efficacy index was 0.99 in group A and 1.04 and 1.03 for group B. Post-operative UDVA [dec] of group A was 0.98±0.15 [0.50 to 1.25] and in group B 0.98±0.13 [0.50 to 1.25] showing a statistically significant difference between groups.

The data from the 3-month follow-up comparing SmartSight classical without active centration and SmartSight NOVA with active centration showed a higher accuracy refraction (SEQ or cylinder) and a better visual acuity in the group with SmartSight NOVA. SmartSight classical and SmartSight NOVA has both shown to be an effective and safe procedure for addressing myopia and myopic astigmatism.