Ultrasound biomicroscopy comparison of ab interno and ab externo scleral fixation of posterior chamber intraocular lenses

PURPOSE: To compare ab interno and ab externo scleral fixation of posterior chamber intraocular lenses (PC IOLs) using ultrasound biomicroscopy (UBM) to determine the centration of IOL optic and the position of the haptics in relation to the sulcus. SETTING: Kasr Eleini Hospital, Cairo University, Cairo, Egypt. METHODS: Consecutive patients with aphakia had ab externo or ab interno scleral fixation of a PC IOL. Ultrasound biomicroscopy was used preoperatively to determine whether the eyes were unsuitable for capsule fixation and 3 and 6 months postoperatively, determine the position of the haptics in relation to the ciliary sulcus, and evaluate centration of the optic. RESULTS: Fifteen eyes of 14 patients were studied. Eight patients had ab externo fixation, and 7 had ab interno fixation. The haptics were located in the sulcus in 31% of cases with ab externo fixation and 29% with ab interno fixation. The difference was not statistically significant. CONCLUSION: Ab interno and ab externo scleral fixation, which are both blind procedures, resulted in comparable low rates of sulcus fixation.