Anterior Chamber Measurements by Pentacam and AS-OCT in Eyes With Normal Open Angles

PURPOSE: To assess the reproducibility and agreement of anterior chamber measurements between the Pentacam (PTC) and the Anterior segment optical coherence tomography (AOCT) in normal healthy eyes with open angle. METHODS: Prospective cross-sectional comparative case series. A total of 162 eyes of 81 healthy volunteers with normal open angle were included in this study. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured with PTC and AOCT. Intra-observer variability and inter-methods agreement of both instruments for ACA and ACD were evaluated. RESULTS: Values of temporal and nasal ACA measured by two instruments were similar, and the results of ACD were also not significantly different between modalities (p>0.01). ACA and ACD measurements by PTC and AOCT showed good intra-observer and inter-method agreements (all >0.9). CONCLUSIONS: PTC and AOCT are presumed to be very useful for the anterior chamber angle examination. They may provide good images and quantitative data about the angle structures including ACA and ACD.

Evaluation of the anterior chamber angle in Asian Indian eyes by ultrasound biomicroscopy and gonioscopy.

PURPOSE: To compare the ultrasound biomicroscopic measurement of the anterior chamber angle in Asian Indian eyes, with the angle width estimated by gonioscopy. MATERIALS AND METHODS: Participants: Patients with open and closed angles attending a glaucoma clinic were recruited for the study. OBSERVATION PROCEDURES: Temporal quadrants of the angles of patients were categorized by gonioscopy as Grade 0 to Grade 4, using Shaffer's classification. These angles were quantified by ultrasound biomicroscopy (UBM) using the following biometric characteristics: Angle opening distance at 250 micro (AOD 250) and 500 micro (AOD 500) from the scleral spur and trabecular meshwork-ciliary process distance (TCPD). The angles were further segregated as "narrow angles" (Schaffer's Grade 2 or less) and "open angles" (Schaffer's Grade 3 and 4). MAIN OUTCOME MEASURES: The UBM measurements were computed in each case and analyzed in relation to the gonioscopic angle evaluation. RESULTS: One hundred and sixty three eyes of 163 patients were analyzed. One hundred and six eyes had "narrow angles" and 57 eyes had "open angles" on gonioscopy. There was a significant difference among the mean UBM measurements of each angle grade estimated by gonioscopy (P < 0.001). The Pearson correlation coefficient between all UBM parameters and gonioscopy grades was significant at the 0.01 level. The mean AOD 250, AOD 500 and TCPD in narrow angles were 58+/-49 micro, 102+/-84 micro and 653+/-124 respectively, while it was 176+/-47 micro, 291+/-62 micro and 883+/-94 micro in eyes with open angles (P < 0.001) respectively. CONCLUSIONS: The angle width estimated by gonioscopy correlated significantly with the angle dimensions measured by UBM. Gonioscopy, though a subjective test, is a reliable method for estimation of the angle width.