Use of ultrasound biomicroscopic evaluation in preoperative planning of penetrating keratoplasty

Purpose. To evaluate the use of ultrasound biomicroscopy (UBM) in examining the status of anterior-segment structures in eyes with corneal opacificati on. Methods. Evaluation with UBM was performed between 1 and 2 weeks before surgery in 21 patients (21 eyes) with corneal opacities who were scheduled for penetrating keratoplasty. UBM findings were correlated with the findin gs noted during penetrating keratoplasty. The efficacy of UBM evaluation wa s calculated in terms of positive and negative predictive values (PPVs and NPVs) for the presence or absence of each finding. Results. Seventeen eyes had either aphakic or pseudophakic bullous keratopathy (ABK or PBK). UBM fi ndings of anterior synechiae, peripheral anterior synechiae, posterior syne chiae, peripheral and sector iridectomies positively correlated with those observed during surgery in five (55.6%) of nine locations, 19 (73.1%) of 26 locations, 12 (80%) of 15 locations, eight (88.9%) of nine locations) and six (85.7%) of seven locations, respectively. The NPVs for these findings w ere 100%, six (54.5%) of 11 locations), 10 (71.4%) of 14 locations, 12 (100 %) of 12 locations, and 14 (100%) of 14 locations, respectively. Correlatio n for findings pertaining to the posterior capsule (PC) were presence of PC /PC remnants [PPV, 13 (92.9%) of 14 locations; NPV, two (66.7%) of three lo cations], presence of central PC tears [PPV, two (66.7%) of three locations ], intactness of PC [PPV, six (85.7%) of seven locations], and PC thickenin g [PPV, 13 (81.25%) of 16 locations; NPV, four (100%) of four locations]. F or vitreous in the anterior chamber, the PPV was eight (100%) of eight loca tions, and NPV was 12 (92.3%) of 13 locations. Pseudophakos-related informa tion in eyes with PBK showed a PPV of 100% for presence, centration, and an atomic location (seven of seven, four of four, and seven of seven locations , respectively). Conclusion. In eyes with corneal opacity, UBM determines t he status of various anterior-segment structures. It is thus a useful adjun ct in the preoperative planning and prognostication of patients requiring p enetrating keratoplasty.