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 opacification. 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 findings noted during penetrating keratoplasty. The efficacy of UBM evaluation was 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 findings of anterior synechiae, peripheral anterior synechiae, posterior synechiae, 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 were 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. Correlation 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 locations], presence of central PC tears [PPV, two (66.7%) of three locations], intactness of PC [PPV, six (85.7%) of seven locations], and PC thickening [PPV, 13 (81.25%) of 16 locations; NPV, four (100%) of four locations]. For vitreous in the anterior chamber, the PPV was eight (100%) of eight locations, and NPV was 12 (92.3%) of 13 locations. Pseudophakos-related information in eyes with PBK showed a PPV of 100% for presence, centration, and anatomic location (seven of seven, four of four, and seven of seven locations, respectively). Conclusion. In eyes with corneal opacity, UBM determines the status of various anterior-segment structures. It is thus a useful adjunct in the preoperative planning and prognostication of patients requiring penetrating keratoplasty.