Reverse pupillary block, in contemporary scleral intraocular lens procedures

Background: To evaluate the frequency and anterior segment optical coherence tomography parameters of patients with scleral fixated intraocular lenses (IOL) and reverse pupillary block (RPB). Methods: Retrospective analysis at a tertiary care centre (Department for Ophthalmology and Optometry, Medical University of Vienna, Austria). We researched our records for patients who underwent scleral fixated IOL implantation from January 2018 till February 2023. Patients were included only if there was at least one adequate post-operative scan of anterior segment optical coherence tomography (AS-OCT) available. Initially, AS-OCT scans were assessed for IOL tilt and decentration employing a 3D scan and then later for anterior chamber angle (ACA), aqueous anterior chamber depth (AQD), pupil diameter and iris-IOL distance using the 2D scan at a 0(degrees) angle. Both an iris-IOL distance of 0 or less and an ACA of more than 70(degrees) were required to define an RPB. Results: A total of 110 patients met the inclusion criteria, 41 were treated using the Carlevale, 33 the four flanged, 24 the Yamane and 12 the Scharioth technique, respectively. RPB was found in 32 patients (29%). Twenty patients with RPB were treated using YAG peripheral iridotomy, mean ACA decreased from 91.91(degrees) +/- 13.77 to 61.02(degrees) +/- 8.52, (p < 0.001), mean AQD decreased from 4.67 mm +/- 0.47 to 4.31 +/- 0.36 mm (p < 0.001) and mean iris-IOL distance increased from -0.09 +/- 0.04 to 0.33 +/- 0.30 (p < 0.001). Conclusions: RPB is found in a third of eyes who have undergone scleral fixated IOL implantation without iridectomy. YAG peripheral iridotomy is a potent option to treat RPB, and subsequently reduce the risk of iris chafing and secondary inflammation or glaucoma.