Changes in Pupil Area during Low-energy Femtosecond Laser-assisted Cataract Surgery.

Alireza Mirshahi,Katharina A Ponto

doi:10.18502/jovr.v14i3.4780

Abstract

PurposeTo study the potential changes in pupil area within low-energy femtosecond-laser assisted cataract surgery (FLACS).MethodsA retrospective assessment of the pupil size was performed in the eyes undergoing FLACS using the Ziemer LDV Z8. We measured the pupil diameters as part of the images taken preoperatively and at the completion of laser pretreatment (after releasing the suction). We calculated the pupil area in 40 eyes of 40 patients (14 right and 26 left eyes). The mean standard deviation (SD) of age of the patients was 74 7.4 years (range: 51-87). Paired t-test was used for statistical analyses. Subgroups were built with reference to age and preoperative pupil area (smaller than or equal to the median versus larger than the median).ResultsThe mean SD axial length, anterior chamber depth, white-to-white distance and lens thickness were 24.01 1.47, 3.23 0.4, 11.97 0.49, and 4.59 0.41 mm, respectively. The mean SD pupil area was 39.33 7.1 mm preoperatively and 39.3 6.75 mm after laser pretreatment. The mean SD change in pupil area was -0.03 2.12 mm. There were no statistically significant changes between preoperative and post-laser pupil areas (P = 0.93, 95% CI: -0.71 to 0.65). Comparisons within subgroups also did not detect pupil area reduction.Conclusion This study did not detect statistically significant changes in pupil area after laser pretreatment using low-energy FLACS. This observation is in contrast to previous studies using other laser platforms.

Highlights

In the subgroup of eyes with larger preoperative pupils, the mean change of the pupil area after Femtosecond laser-assisted cataract surgery (FLACS) did not change significantly; in the group of eyes with a preoperative pupil area of 39.61 mm2 or smaller, it changed from 33.90 ± 4.41 mm2 preoperatively to 34.29 ± 5.00 mm2 after FLACS; and in the group of eyes with a preoperative pupil area larger than 39.61 mm2, it changed from 44.75 ± 4.68 mm2 preoperatively to 44.31 ± 4.02 mm2 after FLACS
In eyes of patients aged 75.5 years or younger, the mean change of pupil area after FLACS was 0.08 ± 1.88 mm2, and in eyes of patients older than the median age of 75.5 years, it was -0.13 ± 2.38 mm2
Preoperative pupil status with post-laser size. This is in contrast to previous studies using other laser platforms that assessed pupil changes in highenergy FLACS

Summary

Introduction

Femtosecond laser-assisted cataract surgery (FLACS) has undergone considerable evolution since its introduction by Nagy et al in 2009.[1,2,3,4] Currently, FLACS is thought to be safe and effective, as reported by several studies.[1, 5, 6]. Researchers believe that increased levels of prostaglandin E2 (PGE2), as measured immediately after laser pretreatment, are responsible for intraoperative narrowing of the pupil.[12,13,14,15] PGE2 is released when ocular tissue is exposed to femtosecond laser cutting side effects.[16]

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