Pupillometric evaluation of α₁-adrenergic blockers in benign prostatic hyperplasia

Abstract

Objectives: The purpose of this study was to evaluate the effects of adrenergic receptor antagonists on pupillary function in patients with benign prostatic hyperplasia (BPH) and to compare the pupillometric alterations between the A-selective blocker tamsulosin and the non-subtype-selective blocker doxazosin. Methods: This retrospective study included 158 men: 58 treated with tamsulosin, 46 with doxazosin, and 54 healthy controls. An automated quantitative pupillography system was used to measure pupillary responses in scotopic (0.04 lux), mesopic (4 lux), and photopic (50 lux) conditions, as well as during dynamic testing after the light was turned off. Demographic, clinical, and medication-related variables were recorded, and correlations between drug exposure duration, International Prostate Symptom Score (IPSS), and pupillometric parameters were analyzed. Results: Both α₁-blocker groups exhibited significantly smaller static and dynamic pupil diameters than controls (p < 0.001). Under scotopic conditions, the mean pupil diameter was 4.24 ± 0.72 mm in the tamsulosin group, 4.75 ± 1.17 mm in the doxazosin group, and 5.30 ± 1.03 mm in controls (p < 0.001 for overall comparison). The reduction was greater with tamsulosin than with doxazosin (p = 0.033). Dynamic pupillometry revealed consistently smaller pupil sizes at all time points in both drug groups, indicating impaired sympathetic dilator activity. No significant correlations were found between treatment duration, IPSS, and pupillometric outcomes. Conclusions: Tamsulosin and doxazosin both attenuate static and dynamic pupillary responses, suggesting reduced sympathetic control of the iris. The more pronounced scotopic constriction with tamsulosin supports its stronger α₁A-receptor affinity and provides quantitative evidence of its association with increased risk of intraoperative floppy iris syndrome. Quantitative pupillometry offers an objective preoperative tool for identifying α₁-blocker users at risk of poor pupil dilation during cataract surgery