Pupillary Dilator Muscle Thickness as a Potential Predictor of Intraoperative Floppy Iris Syndrome

Pupillary Dilator Muscle Thickness as a Potential Predictor of Intraoperative Floppy Iris Syndrome: An Anterior Segment Optical Coherence Study

Intraoperative Floppy Iris Syndrome (IFIS) is a potencial complication encountered during cataract surgery in patients treated with α1-adrenergic receptor antagonists (α1-ARAs) for lower urinary tract symptoms. Therefore, careful assessment of pharmacological history is essential during the preoperative biometric evaluation of patients indicated for cataract surgery. In this study, the investigators expand the standart preoperative assessment by incorporating measurements of iris thickness at the level of the dilator and sphincter pupillae muscles, as well as pupil diameter, using anterior segment optical coherence tomography in patients receiving α1-ARAs. The aim of the study was to determine whether these parameters are associated with the intraoperative risk of IFIS development.

Study Overview

• Status: Completed
• Conditions: Cataract; Age-related Cataract; Intraoperative Floppy Iris Syndrome; Adrenergic Receptor Antagonist Adverse Reaction

Detailed Description

Intraoperative Floppy Iris Syndrome (IFIS) is an unpredictable complication that may occur during cataract surgery in patients diagnosed with lower urinary tract symptoms (LUTS) undergoing therapy with α1-adrenergic receptor antagonists (α1-ARAs). Of all α1-ARAs, tamsulosin is most strongly associated with the development of IFIS. IFIS is characterized by a fluttering, unstable iris, its prolapse into corneal incisions, and intraoperative progressive miosis despite pharmacologically induced mydriasis in the preoperative period. The use of α1-ARAs reduces the tone of the pupil dilator muscle and subsequently leads to its gradual atrophy, which causes laxity of the iris stroma and the development of IFIS during cataract surgery. Based on the presence of individual signs, the investigators distinguish between mild, moderate, and severe forms of IFIS. IFIS symptoms can complicate cataract surgery and increase the risk of complications during and after surgery. During cataract surgery, posterior capsule rupture with lens masses luxation into the vitreous body, damage the iris by the phacoemulsification probe, or prolapse of the vitreous body into the anterior chamber may occur. In the postoperative period, the patient may experience elevated intraocular pressure, persistent photophobia, endophthalmitis, or cystoid macular edema. Ultimately, IFIS can negatively affect the functional outcome of the surgery and leave the patient dissatisfied with permanently reduced vision quality. Anatomical changes in the iris caused by the use of α1-ARAs can be verified using anterior segment optical coherence tomography (AS-OCT). In this study, the authors used AS-OCT as the main instrument for measuring individual iris parameters prior to cataract surgery in patients undergoing α1-ARAs therapy. The goal was to determine whether there is a correlation between the degree of atrophy of the pupillary dilator muscle and the incidence of IFIS development. Among other things, the investigators also focused on measuring pupil diameter. During the study, the incidence of intraoperative complications and the relationship between the duration of α1-ARA use and the development of IFIS were evaluated. In patients, the parameters of the iris in the first eye scheduled for cataract extraction using AS-OCT Carl Zeiss Visante was measured before cataract surgery. The investigators performed AS-OCT measurements under photopic conditions with maximum artificial lighting (>300 lux) and under scotopic conditions in a dark room with the patient covered with a black non-translucent cloth (0 lux). The thickness of the pupillary dilator muscle at half the distance between the scleral spur and the edge of the pupil, the pupillary sphincter muscle at a distance of 0.75 millimeters from the edge of the pupil and the ratio to compensate for possible variability between subjects were evaluated. The investigators also used AS-OCT to measure the pupil diameter without mydriasis under photopic and scotopic conditions. Under scotopic conditions, the pupil size was assessed 30 minutes after inducing artificial mydriasis using a combination of 1% tropicamide and 10% phenylephrine hydrochloride mydriatics, which were applied three times at 10-minute intervals. The horizontal images were taken in the center of the pupil under both light conditions, performing the measurements three times and averaging the resulting values. In addition to iris and pupil parameters, patients´ age, type, and duration of α1-ARA use were determined. The investigators also monitored the development of IFIS during cataract surgery, determining its severity based on the classification established by Chang and Campbell, and the occurrence of intraoperative complications. The cataract surgeons were informed in advance about the risk group of patients. At the beginning of the cataract surgery, phenylephrine at a dose of 0.2 mg/ml was administered to the anterior chamber to induce more pronounced mydriasis and restore iris rigidity. The surgery was performed by experienced surgeons using a temporal approach with the Alcon Centurion Vision System and Alcon Constellation Vision System.

• Study Type: Observational
• Enrollment (Actual): 30

Contacts and Locations

Study Locations

• Czechia
  • Olomouc, Czechia, 77900
    • Department of Ophthalmology, University Hospital Olomouc, Olomouc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients will be recruited from patients examined before cataract surgery at the Department of Ophthalmology of University Hospital Olomouc.

Description

Inclusion Criteria:

• Age related cataract
• Age over 18 years
• Men with diagnosed lower urinary tract symptoms
• History of having taken any systemic α1-adrenergic receptor antagonists for lower urinary tract symptoms
• Signed informed consent
• Performing of pre-operative examination before cataract surgery (best-corrected visual acuity, measurement of refraction, slit lamp and biometric examination)
• Measurement on anterior segment optical coherence tomography under photopic (>300 lux) and scotopic conditions (0 lux)

Exclusion Criteria:

• Congenital or secondary changes in iris morphology - perforating or blunt eye injuries
• Previous uveitis
• LIRE performer
• History of acute ange-closure glaucoma
• Pigment dispersion syndrome
• Pseudoexfoliation syndrome
• Iris tumors
• Previous intraocular surgery
• History of use of miotics, mydriatics and α1-adrenergic agonists

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Patients with lower urinary tract symptoms undergoing therapy with α1-adrenergic receptor antagonist; Patients with lower urinary tract symptoms undergoing therapy with α1-adrenergic receptor antagonists and undergoing cataract surgery

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thickness of pupillary dilator muscle	Thickness of pupillary dilator muscle is measured at half the distance between scleral spur and the edge of the pupil (mm).	preoperatively
Thickness of pupillary sphincter muscle	Thickness of pupillary sphincter muscle is measured at a distance of 0.75 mm from the edge of the pupil (mm).	preoperatively
Ratio of the thickness of pupillary dilator muscle and pupillary sphincter muscle	Ratio of the thickness of pupillary dilator muscle and pupillary sphincter muscle is a dimensionless quantity.	preoperatively
Pupil diameter	Measurement of pupil diameter in a horizontal section in the center of the pupil naturally and after the use of mydriatics using Anterior segment optical coherence tomography (mm).	preoperatively
Development of IFIS during cataract surgery	Development of IFIS - yes/no.	intraoperative
Severity of IFIS during cataract surgery	Determination of severity of IFIS - mild/moderate/severe.	intraoperative
Incidence of intraoperative complications	To find out if there are any intraoperative complications in patients and what the complications are (rupture of the posterior capsule, luxation of lens masses into the vitreous body, damage to the iris by surgical instruments, hyphaema…)	intraoperative

Collaborators and Investigators

• Sponsor: University Hospital Olomouc
• Collaborators: Palacky University
• Investigators: Principal Investigator: Miroslava Maluskova, MD, FEBO, University Hospital Olomouc and Palacky University Olomouc

Study record dates

Study Major Dates

• Study Start (Actual): January 3, 2022
• Primary Completion (Actual): May 31, 2024
• Study Completion (Actual): May 31, 2024

Study Registration Dates

• First Submitted: January 25, 2026
• First Submitted That Met QC Criteria: April 1, 2026
• First Posted (Actual): April 8, 2026

Study Record Updates

• Last Update Posted (Actual): April 8, 2026
• Last Update Submitted That Met QC Criteria: April 1, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Benign Prostatic Hyperplasia; Lower Urinary Tract Symptoms; cataract; Age-related Cataract; Alpha1-adrenergic receptor antagonists; intraoperative floppy iris syndrome
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Urological Manifestations; Eye Diseases; Lens Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Prostatic Hyperplasia; Cataract; Lower Urinary Tract Symptoms
• Other Study ID Numbers: IGA_LF_2022_026

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No