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R. S. Alonso, R. Ambrósio, Jr., B. M. Fontes, A. Paranhos, Jr., M. P. Ventura; Anterior Chamber Morphometry Based on Optical Scheimpflug Images. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3345.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the correlation of anterior chamber angle (ACA) evaluation by noncontact morphometry using anterior chamber tomography (HR Pentacam) with clinical gonioscopy and the ability of HR Pentacam to predict angle occludability.
Prospective masked observational study. Darkroom gonioscopy with Goldmann 3-mirror contact lens was used to classify eyes by the Shaffer grading system. Eyes were divided into open-angle (grade III and IV) and narrow-angle (grade I and II). Anterior chamber angle (ACA), anterior chamber volume (ACV) and anterior chamber depth (ACD) were calculated with HR Pentacam and were correlated with gonioscopy grade to detect occludable angles.
Total of 112 eyes of 56 patients, 74 (66%) open-angle eyes and 38 (34%) narrow-angle eyes were examined. HR Pentacam images revealed mean ACA of 39.2 ± 5.3 degrees for open-angle and 21.2 ± 8.0 degrees for narrow-angle. There was moderate agreement between the two methods with regard to ACA (Kappa=0.51, p<0.001) (Table). ACV and ACD values demonstrated a statistically significant difference comparing open-angle and narrow-angle groups classified in Shaffer Grade and HR Pentacam; 193 ± 36 mm3 ACV for open-angle and 90 ± 25 mm3 ACV for narrow-angle (p<0.0001) and 3.09 ± 0.42 mm3 ACD for open-angle and 1.55 ± 0.64 mm3 ACD for narrow-angle (p<0.0001).
Both ACV and ACD were found to be good predictors of angle occludability. Moderate statistical correlation was observed for morphometry using HR Pentacam and clinical gonioscopy. The most likely explanation for these results is that HR Pentacam software systematically overestimates ACA compared with clinical gonioscopy.
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