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

Purpose: To evaluate the clinical reliability of Pentacam�뱡 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�뱡 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�뱡 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�뱡 using the ROC curve (AUC of UBM, 0.942; AUC of Pentacam�뱡, 0.931). Conclusions: Pentacam�뱡 shows high to moderate correlation of anterior chamber measurements and good agreement compared with UBM. Pentacam�뱡 shows similar ability in diagnosing angle closure compared with UBM and thus is expected to be a good tool in diagnosing angle closure