Real-time corneal thickness changes during phacoemulsification cataract surgery

Abstract

Purpose: To observe the changes in corneal thickness during phacoemulsification cataract surgery and to analyze the influencing factors.

Methods: One hundred two patients (102 eyes) with cataracts undergoing phacoemulsification cataract surgery at Shandong Eye Hospital between July and October 2021 were included. Intraoperative OCT was applied to capture real-time images preoperatively, before and after ultrasonic emulsification, at the end of irrigation aspiration and the end of surgery. Then, the corneal thickness at the above time points was measured using Photoshop software.

Results: The corneal thickness of 102 cataract patients was 511.79 ± 31.46 μm before operation and 512.71 ± 31.51 μm at the beginning of phacoemulsification, which increased by 0.91 ± 1.48 μm (0.2%). At the end of ultrasonic emulsification, the corneal thickness was 521.58 ± 32.75 μm and 8.87 ± 8.71 μm (1.7%) thicker than that before the procedure. After irrigation aspiration, the corneal thickness reached 528.09 ± 33.87 μm, which increased by 6.52 ± 6.38 μm (1.3%) compared with that of the previous step. At the end of the operation, the corneal thickness was 539.19 ± 33.88 μm, 11.09 ± 10.92 μm, and 27.37 ± 13.64 μm thicker than that of the previous step and the preoperative thickness, respectively, with an overall increase of 5.3%. The differences were statistically significant at all time points (all P < 0.001). Correlation analysis showed that postoperative corneal thickness changes were correlated with age, cataract lens nuclear grade, actual phacoemulsification time (APT), effective phacoemulsification time (EPT), average phacoemulsification energy (APE), total surgery time (TST), cell density (CD), maximum cell area (MAX), and cell area standard deviation (SD) (all P < 0.05), while the changes in thickness were not correlated with gender, cell area coefficient of variation (CV), percentage of hexagonal cells (6A), average cell area (AVE), or minimum cell area (MIN) (all P > 0.05).

Conclusions: During phacoemulsification cataract surgery, corneal thickness gradually increases in real time with the increase of perfusion pressure and intraocular manipulation time. The real-time magnitude of intraoperative corneal thickness change is closely related to lens nucleus hardness, corneal endothelial cell density, ultrasound energy, and time for emulsification.

Keywords: Corneal edema,·Intraoperative optical coherence tomography; Corneal thickness; Phacoemulsification cataract surgery.