Postoperative Flare and Corneal Endothelial Cell Loss After Eight-Chop Technique Phacoemulsification: A Prospective Observational Study

TL;DR

This study shows that the Eight-chop phacoemulsification technique causes minimal inflammation and very low corneal cell loss after surgery.

Contribution

The study is the first to systematically investigate the relationship between postoperative inflammation and corneal cell loss using the Eight-chop technique.

Findings

Postoperative aqueous flare peaked on Day 7 but was still low overall.

Corneal endothelial cell loss averaged less than 2% at both Week 7 and Week 19.

Early postoperative flare did not predict corneal cell loss or IOP reduction.

Abstract

Objectives: The Eight-chop technique is a mechanically based nuclear segmentation method designed to improve surgical efficiency and reduce intraocular tissue stress during phacoemulsification. Early postoperative aqueous flare serves as an objective indicator of surgical invasiveness, whereas corneal endothelial cell density (CECD) loss represents a structural measure of endothelial injury. Although both parameters are clinically important, their relationship has not been systematically investigated in the context of this newer mechanical fragmentation approach. Methods: This prospective observational study included 118 eyes from 70 non-diabetic patients undergoing uncomplicated Eight-chop phacoemulsification. Aqueous flare was measured preoperatively and at postoperative Day 1, Day 7, Week 7, and Week 19 using laser flare photometry. CECD was evaluated preoperatively and at Weeks 7 and 19. Changes over time were analyzed using paired t-tests. Linear mixed-effects models (random intercept = patient ID) were constructed to assess predictors of CECD loss and postoperative intraocular pressure (IOP) reduction. Explanatory variables included Day 1 flare, age, preoperative CECD, nucleus hardness (Emery-Little grade), cumulative dissipated energy (CDE), and irrigation fluid volume. Results: Postoperative flare increased significantly at all time points (all p < 0.001), peaking on Day 7 (16.7 ± 9.21 photon counts/ms). CECD loss was extremely small, averaging 1.38% at Week 7 and 1.46% at Week 19. In mixed-effects models, Day 1 flare was not associated with CECD loss at Week 7 (p = 0.35) or Week 19 (p = 0.85). Significant predictors of CECD loss included Emery-Little grade (p = 0.004 at Week 7; p = 0.025 at Week 19), with borderline contributions from CDE and irrigation volume. IOP decreased significantly at Weeks 7 and 19; however, Day 1 flare did not predict IOP reduction. Conclusions: Eight-chop phacoemulsification produced uniformly low postoperative inflammation and exceptionally small corneal endothelial cell loss. Early postoperative flare did not predict CECD loss, suggesting that the Eight-chop technique provides a highly standardized, low-invasiveness surgical environment. These findings suggest that the Eight-chop technique lowers ultrasound energy requirements and may help reduce corneal endothelial stress relative to standard phacoemulsification.