Purpose: To evaluate the anatomic relationships of the implantable contact lens (ICL) and the phakic refractive lens (PRL) posterior chamber phakic intraocular lenses (PCP IOL) using ultrasound biomicroscopy (UBM).
Material and methods: Seventeen phakic myopic eyes corrected with ICL, and 14 phakic myopic eyes that had had PRL implantation, were examined retrospectively using UBM. The main parameters measured and compared were anterior chamber depth, central and peripheral distance between PCP IOL and the crystalline lens, and exact lens haptic position.
Results: The mean distance between the PCP IOL and the central endothelium was 2398+/-203 microm and 2640+/-230 microm in the ICL and PRL groups, respectively. The central vault between the implant and the crystalline lens was greater in eyes with ICL (ICL, 402+/-194 microm; PRL, 256+/-187 microm, p<0.05). However, the incidence of lens contact on the peripheral level was higher in the ICL group (41%) than in the PRL group (29%), and the difference between the two implants in the peripheral crystalline lens-PCP IOL distance was significant (p<0.05). Both IOL haptics appeared to be correctly positioned in the sulcus in 13 (76%) eyes of the ICL group, and on the zonule in eight eyes (57%) of the PRL group.
Conclusions: PCP IOL implantation is a safe procedure for the correction of high myopia with regard to refractive results. UBM provides a unique tool to noninvasively evaluate the relations of these implants within the posterior chamber, and helps to analyze the mechanisms of crystalline lens and iris complications.