Pupil Size and Choroidal Thickness Changes With Tamsulosin vs. Silodosin in Benign Prostatic Hyperplasia Patients

Benign prostatic hyperplasia (BPH) is a common disease in men and is treated with alpha-blockers, particularly tamsulosin and silodosin. Studies suggest that these drugs may affect α1a receptors in the iris dilator muscle, causing structural changes in the iris and pupillary disturbances, and increasing the risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery.

Main objective: To compare the effect of tamsulosin and silodosin on pupil size and choroidal thickness in patients with BPH.

Men aged 50 years and older with a definitive diagnosis of BPH who have no prior history of alpha-blocker use will be enrolled in one of the two treatment arms - tamsulosin or silodosin. Assessments will be conducted at two time points - before the start of treatment and after three months of continuous.

* Pupillography will be performed at three standard illumination levels - scotopic 0.04 lux, mesopic 4 lux, and photopic 50 lux - with pupil diameter automatically recorded under each condition using the MS-39 device (manufactured by CSO, Italy). * Choroidal assessment will use EDI-OCT (Heidelberg) macular imaging, measuring choroidal thickness at the subfoveal position and at 500 and 1000 micron nasal and temporal points.

To reduce daily fluctuations related to circadian rhythm, all imaging will be performed within a fixed window of 9-11 a.m. by a single trained operator.

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Key information

Conditions

Benign Prostatic Hyperplasia Choroid Eye Diseases Genital Diseases Genital Diseases, Male Iris Disease Iris Diseases Male Urogenital Diseases Prostatic Diseases Prostatic Hyperplasia Silodosin Tamsulosin Tomography, Optical Coherence Urogenital Diseases Uveal Diseases

Age range

50 year and older

Sex eligibility

Male

Study type

Interventional

Phase

Phase 4

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Men ≥ 50 years of age with a definitive diagnosis of BPH by a collaborating urologist.
Patients with moderate symptoms based onthe International Prostate Symptom Score (IPSS): score 8 to 19
No prior use of any alpha-blocker (tamsulosin, silodosin, doxazosin, etc.)
Vision adequate for imaging
Consent to participate in the study
No history of any intraocular surgery; no active or structural ocular disease affecting the pupil/iris, such as glaucoma, uveitis, pseudoexfoliation syndrome, pigment dispersion syndrome.
No use of pupil-affecting eye drops within the past 2 weeks

Exclusion criteria

High myopia (SE ≤ -6.00 D) or axial length > 26.5 mm, in order to control for its effect on choroidal thickness
History of trauma or injury to the iris
Insufficient image quality during assessments
Patient unwilling to continue participation in the study
Occurrence of unwanted systemic adverse effects during the study
Improper medication adherence during the study
Diabetes
Hypertension

Treatment and study plan

tamsulosin 0.4mg

Drug

Tamsulosin 0.4 mg, daily

Silodosin 8 mg

Drug

Silodosin 8 mg, daily.

Primary outcomes

Mean change in pupil diameter

Time frame: From baseline to the third month.

Mean change in pupil diameter under scotopic, mesopic, and photopic lighting conditions.
Mean change in choroidal thickness

Time frame: From baseline to the third month.

Study contacts

Contact information is provided by the study sponsor or research team.

Mohsen Pourazizi, Assistant Professor

CONTACT

[email protected]

98 + 09379578055

Sponsors and collaborators

Lead sponsor

Mohsen Pourazizi

Other

Registry information

Official study title

Comparison of Tamsulosin and Silodosin on Pupil Size and Choroidal Thickness in Patients With Benign Prostatic Hyperplasia

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Aug 3, 2026
Registry last updated: Aug 3, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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