Purpose: The aim of this study was to quantify changes and reversibility in pupil dilation and iris dilator muscle region thickness associated with introduction and subsequent discontinuation of tamsulosin in patients naïve to this drug with the aid of an anterior OCT system.
Methods: The study was carried out on 7 patients (14 eyes) naïve to tamsulosin and with benign prostatic hypertrophy (BHP). Measurements taken by Vistante OCT were done pre- and post-dilation of the following: pupil size, iris dilator muscle region (DMR) thickness, sphincter muscle region (SMR) thickness, and anterior chamber depth. These measurement were taken at Day 0 (tamsulosin naive), Day 30 (after one month of tamsulosin, the treatment period) and day 60 (after one month of no tamsulosin, the discontinuation period).
Results: Post-dilation pupil diameter significantly increased during the discontinuation period (P = 0.047). Iris DMR thickness measurements post-dilation significantly decreased during treatment (P = 0.00044), discontinuation (0.00011), and combined periods (P = 0.000050). Anterior chamber depth measurements in post-dilation were significantly decreased during treatment (P = 0.0016), discontinuation (P = 0.017), and combined periods (P = 0.00022).
Conclusion: Tamsulosin discontinuation effectively increases dilated pupil size, a measure that has been inversely linked to IFIS incidence pre-operatively. Decreased DMR thickness in this short term likely illustrates changes aside from atrophy, such as vascular changes. Decreased anterior chamber depths suggest aqueous humor production is decreased as well.
Keywords: Benign prostatic hypertrophy; Cataract surgery; Flomax; Intraoperative floppy iris syndrome; Optical coherence tomography; Tamsulosin.