Pupil Status with Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification: An Intraindividual Comparative Study

PURPOSE: To compare the pupil changes in low-energy femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification (CP) intraindividually. PATIENTS AND METHODS: A retrospective review of registered surgical data from patients that undergone uncomplicated cataract surgery in a single centre, with randomly assigned femtosecond laser–assisted cataract surgery (FLACS) to one eye and conventional phacoemulsification (CP) to the other, was performed. The recorded pupil images were evaluated at pre and post laser treatment (after suction release) and at several surgical timepoints for both techniques (FLACS and CP). Pupil areas were calculated and compared in the same eye undergone FLACS (pre vs post laser treatment), between eyes (CP vs FLACS) in the same patient and between groups. Subgroups were built regarding age and ocular comorbidity. RESULTS: This study involved a total of 164 eyes of 82 patients (55 female, 27 male). No statistical differences regarding the total duration of surgery (p=0.805) between FLACS and CP. Pupil measurements between pre and post laser treatment in the FLACS group showed no statistically significant differences (p=0.107). The mean change in pupil area from the beginning until the end of surgery (total variation) was 6.59±2.08 mm(2) in the FLACS group and 6.67±2.13 mm(2) in the CP group, associated to less narrowing of pupil area with FLACS, although not statistically significant (p=0.080). Comorbidity group analysis revealed less, but not significant, pupil narrowing with the FLACS technique (p=0.071). No statistically significant differences between FLACS and CP concerning age subgroups were registered. CONCLUSION: This study shows no significant pupil changes, namely myosis, after low-energy FLACS pre-treatment. Comparison between techniques showed less pupil variation in FLACS as compared to CP, more markedly in eyes with comorbidities (particularly with shallow anterior chamber), although non-statistically significant.