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Comparative Study
. 2025 Jun;263(6):1597-1603.
doi: 10.1007/s00417-025-06748-2. Epub 2025 Feb 3.

Exploring the impact of pupil expansion techniques on cataract surgery: unveiling key complications and clinical outcomes: a comparative analysis of 1266 eyes

Asaf Achiron  1 , Tal Yahalomi  2 , Michael Ostrovsky  1 , Eliya Levinger  1 , Eyal Cohen  1 , Omar Elhaddad  3   4 , Derek Tole  3 , Kieren Darcy  3 , Raimo Tuuminen  5   6
Affiliations
Comparative Study

Exploring the impact of pupil expansion techniques on cataract surgery: unveiling key complications and clinical outcomes: a comparative analysis of 1266 eyes

Asaf Achiron et al. Graefes Arch Clin Exp Ophthalmol. 2025 Jun.

Abstract

Background: In cataract surgery, inadequate pupil dilation presents a major surgical challenge by narrowing the operation field and restricting visibility and movement. We aim to compare cataract surgery complication rates and clinical outcomes using different pupil expansion methods.

Methods: This retrospective cohort study grouped patients according to four techniques of mechanical pupil expansion techniques: sphincterotomy (N = 339), iris stretching (N = 242), iris hooks (N = 391) and expansion rings (N = 294). Incidences and odds ratios for major complications and outcomes were compared between the groups.

Results: This single-center study included 1266 adult patients who underwent routine cataract surgery with mechanical pupil dilatation. The mean (± SD) age was 75.5 (± 13.0) years and 727 (57%) patients were male. The risk of pseudophakic cystoid macular edema (PCME) did not differ between the groups. Iris hooks were associated with the highest incidence of posterior capsular rupture (PCR) (3.3%) as compared to sphincterotomy, stretching and expansion rings (0.9%, 0.4% and 1.4%, respectively, P = 0.016). However, this effect was not supported by multivariable analysis. Zonular dialysis tended to be higher among eyes operated with iris hooks and pupil expansion rings, compared with iris stretching and sphincterotomy (2.0% and 1.7%, respectively, P = 0.058) and was found to be independently associated with a specific mechanical pupil expansion method on multivariable analysis (P = 0.050). No differences were observed for other complications, intraocular pressure or best-corrected visual acuity (VA) gain. Surgeon seniority was a significant protective factor from postoperative uveitis on multivariable analysis (P = 0.032).

Conclusions: Our large cohort study found no difference between the groups regarding major complications or clinical outcomes, suggesting that all four methods may be equally safe.

Key messages: WHAT IS KNOWN : • In cataract surgery, inadequate pupil dilation presents a major surgical challenge by narrowing the operation field and restricting visibility and movement. • Different pupil dilation methods have been used, ranged from topical and intracameral mydriatics and visco-mydriasis to mechanical dilation maneuvers. • Four principal techniques of mechanical pupil expansion, including sphincterotomies, manual iris stretching, iris retracting hooks and pupil expansion rings, are available.

What is new: • This single-center study included 1266 adult patients found no difference between the groups regarding major complications or clinical outcomes such as pseudophakic cystoid macular edema (PCME), posterior capsular rupture, zonular dialysis, intraocular pressure, uveitis or best-corrected visual acuity gain. • Surgeon seniority was a significant protective factor from postoperative uveitis.

Keywords: Cataract surgery; Posterior capsular rupture; Pseudophakic cystoid macular edema; Pupil expansion; Zonular dialysis.

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Conflict of interest statement

Declarations. All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed in this manuscript. All procedures performed in studies involving human participants were in accordance with the ethical standards and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study received the local ethics committee approval (CORN/SE/2021–2022/02 and was presented to the local audit authority) and adhered to the tenets of the Declaration of Helsinki. Conflict of interest: None.

Figures

Fig. 1
Fig. 1
Illustration of different mechanical pupil expansion methods
Fig. 2
Fig. 2
Number of operated eyes over the study period in regard to different mechanical pupil expansion methods
See this image and copyright information in PMC

References

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