Dilated Pupil Vertical-to-Horizontal Ratio as a Predictor of Intraoperative Floppy Iris Syndrome.

PURPOSE: To investigate whether intraoperative floppy iris syndrome (IFIS) can be predicted from pupil morphology, including vertical pupil elongation and pupillary diameter.

SETTING

Shiga University of Medical Science Hospital, Shiga, Japan.

DESIGN

Retrospective observational study.

METHODS

Patients who underwent standalone phacoemulsification cataract surgery between November 2022 and April 2023 were retrospectively reviewed. In bilateral cases, only the first operated eye was included. Eyes with prior ocular surgery or conditions affecting pupil morphology were excluded. Surgical videos were reviewed to assess pupil morphology parameters, including the pupil vertical-to-horizontal ratio (PVHR) and the composite pupil-to-corneal diameter ratio (CPCDR) at the beginning of surgery, and to evaluate IFIS incidence. IFIS incidence was treated as the outcome variable. Explanatory variables comprised age, sex, hypertension, diabetes mellitus, α1-adrenergic antagonist use, and pupil morphology parameters. Associations were evaluated using logistic regression.

RESULTS

A total of 263 patients (263 eyes) were included, of which 23 eyes (8.7%) developed IFIS. PVHR was significantly higher in eyes with vs without IFIS (median: 1.06 vs 1.03; p < 0.001), while CPCDR was significantly lower (0.56 vs 0.70; p < 0.001). In the multivariable logistic regression analysis, PVHR (odds ratio: 4.06; p = 0.0005) and CPCDR (odds ratio: 0.43; p < 0.0001) were independently associated with IFIS.

CONCLUSIONS

Vertical pupil elongation and poor dilation after pharmacologic mydriasis were independently associated with IFIS. Assessment of pupil shape, in addition to pupil size, may improve preoperative identification of eyes at risk for IFIS.