Qualitative analysis of changes in the posterior segment of the eye wich femtosecond laser–assisted cataract surgery

Abstract

Purpose: Analysis of the qualitative changes in the posterior eye segment structures – choroid thickness (CT) and distance height of vitreous posterior hyaloid membrane (VPHM) from retina by spectral optical coherence tomography (SOCT) method in femtosecond laser–assisted cataract surgery (FLACS). Methods and Materials: 46 eyes with immature cataract and retinal SOCT possibility before the operation. Average corrected visual acuity – 0.3±0.05; eye length - 22.51±0.9 mm; IOP – 20 mm Hg; age - 65 years. Before and after surgery (1, 3, 5 days), SOCT of vitreoretinal interface and choroid was performed, RTVue XR 100 «Avanti», Optovue. Group 1, 24 patients, ultrasound FEM of cataract, «Stellaris», B&L. Group 2, 22 patients – FLACS, LenSx, Alcon. Capsulorhexix diameter – 4.9-5.2 mm (energy 12.5 μJ). Fragmentation of the lens nucleus by «chop», «cylinder» methods (energy 10-15 μJ). The main corneal incision – 2.5 mm (energy 5 μJ). Phakoaspiration on «Stellaris», elastic IOLs were implanted. FLACS duration – 9-10 minutes, femtolaser effect ≤ 2 minutes. Results: Before the surgery CT in Group 1 was 253.1±62.1 microns. In 1, 3, 5 days after FEM of cataract CT were 310.4, 262.7, 258.1 microns. Distance height of VPHM before the surgery was 400.1 microns. In 1, 3, 5 days after surgery – 505.6, 492.7, 500.3 microns. In Group 2 before the surgery CT was 256.4±60.3 microns. In 1, 3, 5 days after FLACS CT were 333.1, 279.4, 259.1 microns. Distance height of VPHM before the surgery – 366.2 microns. In 1, 3, 5 days after FLACS – 510.8, 506.2, 508.9 microns. Reactive thickening of the choroid after surgery was determined in both groups. Group 1, 1th day – 57.3 microns (22.6%). By the 5th day CT became initial. Distance height of VPHM increased by 105.5microns. By the 5th day the situation was not changed. Group 2, FLACS, thickening of CT per 1 day is 76.7 microns, (29.9%). By the 5th day CT returned to previous values. VPHM was increased by 144.6 microns. By the 5th day the situation was not changed. Conclusion: Increase of TC and distance height of VPHM in the early postoperative period was noticed in the both groups. After FLACS big figures are conditioned apparently by intraoperative vacuum effect and/or sudden IOP changes during femtolaser stage. Return of CT to initial state indicates processes reversibility. Patients with vitreomacular adhesion when FLEC are highly risky of vitreomacular traction.