Does Further Lowering Intraoperative Intraocular Pressure Reduce Surgical Invasiveness in Active-Fluidics Eight-Chop Phacoemulsification? A Fellow-Eye Comparative Study - Abstract

Sep 30, 2026

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Background: Active-fluidics phacoemulsification can maintain anterior chamber stability at lower intraoperative intraocular pressure (IOP) levels, but whether further reducing IOP alone lowers invasiveness during Eight-Chop phacoemulsification remains unclear. Methods: In a prospective fellow-eye comparative study, 56 non-diabetic patients (112 eyes) underwent Eight-Chop phacoemulsification using the Centurion Vision System with active fluidics, with one eye at 55 mmHg and the fellow eye at 28 mmHg. Results: Lowering IOP did not reduce invasiveness; phaco and aspiration times increased, while operative time, CDE, irrigation volume, aqueous flare, CECD outcomes, corneal morphology, and postoperative IOP showed no significant differences. Conclusions: Further IOP reduction under active-fluidics control offered no measurable short-term clinical advantage when chamber stability was already ensured.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages18

Reading Time45 min

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Abstract

Background

Methods

Results

Conclusions

1. Introduction

2. Materials and Methods

2.1. Ethical Considerations

Article Does Further Lowering Intraoperative Intraocular Pressure Reduce Surgical Invasiveness in Active-Fluidics Eight-Chop Phacoemulsification? A Fellow-Eye Comparative Study Tsuyoshi Sato Academic Editor: Brent Siesky Received: 10 December 2025 Revised: 23 December 2025 Accepted: 31 December 2025 Published: 4 January 2026 Copyright: © 2026 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. Department of Ophthalmology, Sato Eye Clinic, Nemoto 3-3, Matsudo-shi 271-0077, Chiba-ken, Japan; [perfect-eightchop@sato-ganka.com](perfect-eightchop@sato-ganka.com) Abstract Background: Active-fluidics phacoemulsification can maintain anterior chamber stability at lower intraoperative intraocular pressure (IOP) levels. However, whether reducing IOP alone—without additional stabilizing technologies such as the Active Sentry handpiece—can decrease surgical invasiveness during Eight-Chop phacoemulsification remains unclear. Methods: In this prospective fellow-eye comparative study, 56 non-diabetic patients (112 eyes) underwent Eight-Chop technique phacoemulsification using the Centurion Vision System with active fluidics. One eye was randomly assigned to a standard-IOP setting (55 mmHg; high-IOP group) and the fellow eye to a reduced-IOP setting (28 mmHg; lowIOP group) . Intraoperative parameters—including operative time, phaco time, aspiration time, cumulative dissipated energy (CDE), and irrigation volume—were recorded. Postoperative outcomes included aqueous flare (laser flare photometry), corneal endothelial cell density (CECD) and CECD loss, corneal morphology (central corneal thickness [CCT], coefficient of variation [CV], percentage of hexagonal cells [PHC]), and IOP. Linear mixedeffects models with patient ID as a random effect were used for all paired-eye comparisons. Results: Lowering the intraoperative IOP did not reduce surgical invasiveness. Phaco time was significantly longer in the low-IOP group (16.2 ± 5.22 s vs. 13.9 ± 4.40 s; p = 0.001), and aspiration time was also longer (75.0 ± 18.3 s vs. 69.0 ± 17.9 s; p = 0.033) . No significant differences were found in operative time (5.08 ± 1.10 min vs. 4.82 ± 1.13 min; p = 0.082), CDE (5.93 ± 1.87 vs. 5.56 ± 1.90; p = 0.099), or irrigation volume (26.6 ± 7.71 mL vs. 25.2 ± 7.35 mL; p = 0.214) . Postoperative outcomes were similarly comparable. Aqueous flare showed no significant differences at any time point (e.g., day 1: 14.8 ± 5.10 vs. 14.5 ± 4.76 ph/ms; p = 0.655) . Mean CECD loss remained small in both groups and did not differ significantly (7 weeks: −0.82 ± 1.05% vs. −0.98 ± 1.16%, p = 0.460; 19 weeks:−0.93 ± 1.38% vs. −1.28 ± 1.69%, p = 0.239) . Corneal morphological parameters (CCT, CV, PHC) and postoperative IOP also showed no significant differences between settings. Conclusions: In this fellow-eye comparative study, lowering intraoperative intraocular pressure from conventional to near-physiologic levels under active-fluidics control did not reduce surgical invasiveness during Eight-chop phacoemulsification. No additional benefits were observed in terms of endothelial cell preservation, postoperative inflammation, or overall surgical performance. These findings indicate that, when chamber stability is already ensured by a low-invasive fragmentation strategy, further reduction in intraoperative IOP alone does not confer measurable short-term clinical advantages. Keywords: aqueous flare; cataract surgery; corneal endothelial cell; eight-chop technique; phacoemulsification; low intraocular pressure setting 1. Introduction Since its introduction in 1967, phacoemulsification has become the global standard for cataract surgery [1] . Although continuous technological innovations have greatly enhanced the safety and efficiency of the procedure, maintaining intraoperative anterior chamber stability remains a critical

FAQs

What clinical question does the study address about intraoperative IOP?

It evaluates whether further lowering intraoperative intraocular pressure, using active-fluidics control during Eight-Chop phacoemulsification, reduces surgical invasiveness.

How were patients assigned to different IOP settings in this fellow-eye study?

Fifty-six non-diabetic patients (112 eyes) were followed in a prospective fellow-eye design: one eye received a standard setting (55 mmHg) and the fellow eye received a reduced setting (28 mmHg), both during Eight-Chop phacoemulsification under active fluidics.

What were the main findings regarding surgical invasiveness and key postoperative outcomes?

Lowering intraoperative IOP did not reduce invasiveness. Phaco time and aspiration time were longer, while operative time, cumulative dissipated energy, irrigation volume, aqueous flare, corneal endothelial cell loss, corneal morphology parameters, and postoperative IOP showed no significant differences.

Sep 30, 2026

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