PURPOSE: To evaluate anterior segment modifications after penetrating keratoplasty (PKP), previous anterior chamber intraocular lens (IOL) removal, and Verisyse IOL (AMO) implantation over the iris or under the iris for the treatment of pseudophakic bullous keratopathy (PBK) using ultrasound biomicroscopy. SETTING: Department of Ophthalmology, Poitiers University Hospital, Poitiers, France. METHODS: A prospective randomized comparative case series included 27 patients (27 eyes) with PBK who had PKP and implantation of a Verisyse VRSA54 aphakic IOL. The IOL was implanted over the iris in 13 patients (Group A) and under the iris in a reversed position in 14 patients (Group B). Ultrasound biomicroscopy scans 6 months after surgery measured central anterior chamber depth (ACD), iris thickness (IT), distance of the haptics from the corneal endothelium (CED), distance of the haptics from the ciliary body (CBD), angle opening distance (AOD) 500 mum from the scleral spur (AOD500) and the iridocorneal angle theta on the 4 o'clock meridian lines (AOD3; AOD9; AOD12; AOD6/theta12, theta6, theta3, theta9). RESULTS: No significant difference was found in IT, CBD, or AOD12 between Group A and Group B (P >.05). In Group B, the mean ACD was deeper by approximately 55% (P = .008); CED3 was larger by 69% (P = .0162), CED9 by 80% (P = .0128), AOD3 by 57% (P = .0309), AOD9 by 140% (P = .0057), and AOD6 by 44% (P = .0399); and theta3 was wider by 52% (P = .046), theta9 by 123% (P = .0068), theta12 by 50% (P = .0492), and theta6 by 81% (P = .0237). CONCLUSION: Ultrasound biomicroscopy showed that in eyes that had PKP with Verisyse IOL enclavation to the posterior plane of the iris, which involved posterior translation of the iridal plane, the ACD was significantly deeper and the CED and AOD were significantly larger than in eyes with anterior enclavation of the IOL.