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Retrospective Cohort Study
Copyright: ©Author(s) 2026. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial (CC BY-NC 4.0) license. No commercial re-use. See permissions. Published by Baishideng Publishing Group Inc.
World J Ophthalmol. Sep 12, 2026; 10(1): 122273
Published online Sep 12, 2026. doi: 10.5318/wjo.122273
Impact of surgical start time on error rates in cataract surgery: A retrospective cohort study
Kevin Y Wu, Samuel Farag, Natalie Kearn, Christian Goguen, Ananda Kalevar
Kevin Y Wu, Samuel Farag, Christian Goguen, Ananda Kalevar, Division of Ophthalmology, Department of Surgery, University of Sherbrooke, Sherbrooke J1K 2R1, Québec, Canada
Natalie Kearn, Department of Medicine, Queen’s University, Kingston K7L 3N6, Ontario, Canada
Author contributions: Wu KY, Farag S, Kearn N, Goguen C, and Kalevar A performed the literature review and wrote and edited the manuscript; Wu KY, Farag S, and Kearn N analyzed and interpreted the data; Wu KY, Farag S, and Goguen C wrote the protocol; Farag S collected the data. All authors approved the final manuscript.
AI contribution statement: The manuscript did not use any AI software. The authors take full responsibility and accountability for all content of this manuscript.
Supported by Fédération des Médecins Résidents du Québec, No. 2024-04.
Institutional review board statement: This project was approved by the Ethics Committee of Integrated University Health and Social Services Centre of Estrie - Sherbrooke University Hospital Center (Approval No. 2024-5172).
Informed consent statement: The retrospective design of this study, utilizing existing medical records, prevented researchers from establishing direct contact with participants. As a result, consent for publication does not apply.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: The dataset used and analyzed during the study are available from the corresponding author on reasonable request.
Corresponding author: Kevin Y Wu, MD, Division of Ophthalmology, Department of Surgery, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke J1K 2R1, Québec, Canada. yang.wu@usherbrooke.ca
Received: April 15, 2026
Revised: May 20, 2026
Accepted: June 8, 2026
Published online: September 12, 2026
Processing time: 148 Days and 11.8 Hours
Abstract
BACKGROUND

Surgical errors remain an ongoing concern in ophthalmology, particularly in high-volume procedures such as cataract surgery, where even low complication rates translate into significant patient impact. Factors such as surgical start time and surgeon fatigue have been proposed as potential contributors to intraoperative complications, though evidence within ophthalmology remains limited and inconsistent. While some studies in other surgical specialties suggest time-of-day effects on outcomes, data specific to ophthalmology are sparse, and the extent to which surgical timing influences performance remains unclear.

AIM

To assess whether the timing of surgery influences the rate of surgical errors and complications during cataract operations.

METHODS

A retrospective cohort study was conducted at a university center in Sherbrooke, Québec, Canada. We included adults who underwent primary cataract surgery from 2006-2023. Electronic medical records were reviewed for baseline demographics, intraoperative parameters, and postoperative outcomes. Complication rates were compared across hourly time intervals. Continuous and categorical variables were analyzed using appropriate descriptive statistics, and associations between surgical timing and complication rates were assessed using a modified Poisson regression model with statistical significance set at P < 0.05.

RESULTS

A total of 32762 cataract surgeries were included in the analysis, with an overall complication rate of 1.14%. Temporal analysis across the surgical day (7:00 to 15:00) demonstrated no statistically significant variation in complication rates, which ranged from 0.8% to 1.7%. The highest complication rate was observed at 13:00 (1.66%), while the lowest occurred at 15:00 (0.76%); however, these differences were not statistically significant. No consistent trend in complication rates was observed as the day progressed, and confidence intervals overlapped across all time periods.

CONCLUSION

Surgical start time does not appear to significantly influence intraoperative complication rates in cataract surgery. These findings support the safety of current scheduling practices within standard operating hours and suggest that concerns regarding time-of-day effects may be overstated in this context. Future research should focus on identifying other modifiable factors that may contribute to surgical errors and optimizing strategies to further enhance patient safety and surgical outcomes.

Keywords: Cataract surgery; Surgical start time; Intraoperative complications; Surgical errors; Surgeon fatigue; Ophthalmology; Retrospective; Patient safety; Phacoemulsification; Surgical scheduling

Core Tip: This large retrospective cohort study evaluates whether surgical start time influences intraoperative complication rates in cataract surgery. Analyzing over 32000 cases, we found no significant variation in complication rates across the surgical day. These findings challenge assumptions that surgeon fatigue or time of day meaningfully impact surgical performance within standard operating hours. By isolating surgeon-related factors in a high-volume, standardized procedure, this study provides robust evidence supporting current scheduling practices and highlights the need to investigate alternative contributors to surgical error.

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