Ultrasound biomicroscopy for the assessment of zonules after ocular trauma

Abstract

Purpose To evaluate the role of ultrasound biomicroscopy (UBM) as a method for assessing the zonules after trauma to the anterior segment. These patients might develop traumatic cataract or glaucoma requiring surgery. If occult zonular defects can be identified preoperatively, this might lead to a modified surgical technique and improved outcomes. Design Retrospective observational case series. Participants Fifty-nine patients who were referred for UBM after anterior segment trauma. Methods UBM examinations were performed using the Humphrey Instruments Ultrasound Biomicroscope equipped with a 50-mHz transducer. A plastic eyecup filled with 2% methylcellulose solution was used in each case. The chart and UBM images of all anterior segment trauma patients examined between 1995 and 2000 were reviewed. The age, gender, and mechanism of injury were recorded for each patient. Follow-up data were obtained from the referring physician in patients who subsequently underwent ocular surgery. Main outcome measures The number of studies judged to be of adequate quality to evaluate zonules was noted, and the number of cases in which zonular defects were found was recorded. The number of cases in which surgery was subsequently performed was noted, and postoperative results were obtained. Results Fifty-nine charts and 60 UBM studies were reviewed. Forty-nine studies were judged to be adequate for imaging zonules. Most poor-quality studies were in the early years of the study. Further analysis was carried out on the reliable studies. Occult zonular defects were identified in 21 of 49 patients (42.9%). Thirty-one patients went on to have cataract, filtering, and/or vitreoretinal surgery. One surgeon (ACS) performed 25 of the surgical cases, for which a summary is provided. Referring surgeons found the information helpful in surgical planning and anticipating complications in reliable study cases. Conclusions UBM is an effective method for identifying occult zonular damage in patients with anterior segment trauma. There is a significant learning curve in the examination technique. The ability to diagnose zonular rupture preoperatively is of significant benefit to the surgeon and might reduce the chance of intraoperative complications.