Comparison of Measurement of Anterior Segment Parameters Between Scheimpflug Camera and Ultrasound Biomicroscopy

ABSTRACT

PURPOSE: To evaluate the clinical reliability of Pentacam(R) by comparing anterior chamber parameters measured by Oculus Pentacam system (Oculus Inc., Germany) and Hi-scan ultrasound biomicroscopy (OPTIKON 2000, Rome, Italy) in primary angle closure (PAC) and normal patients. METHODS: A prospective study was performed from June 2006 to January 2007. Fifty-one eyes in 26 primary angle-closure patients and 39 eyes in 20 normal control patients, for a total of 90 eyes of 46 patients were recruited from glaucoma out-patient clinics. The correlation and agreement of both measurements of anterior chamber depth and anterior chamber angle measured by UBM and Pentacam(R) were calculated. Sensitivity and specificity of each tool were also compared and the diagnostic value of angle closure was examined. RESULTS: Anterior chamber depth measured by UBM and Pentacam(R) showed strong correlation in the normal control group (r=0.821) and PAC group (r=0.957). Anterior chamber angle showed moderate correlation in the normal control group (r=0.523) and PAC group (r=0.456) while good agreement was also observed. In diagnosing angle closure, anterior chamber measurements appear similar in UBM and Pentacam(R) using the ROC curve (AUC of UBM, 0.942; AUC of Pentacam(R), 0.931). CONCLUSIONS: Pentacam(R) shows high to moderate correlation of anterior chamber measurements and good agreement compared with UBM. Pentacam(R) shows similar ability in diagnosing angle closure compared with UBM and thus is expected to be a good tool in diagnosing angle closure.