Biometric study of acute-angle-closure glaucoma using Orbscan and echography

Purpose: To study acute-angle-closure glaucoma (AACG) biometry using Orbscan and echography. Material and methods: We prospectively studied 200 normal eyes of 100 patients (including eyes with ametropia), 50 eyes of 25 patients before peripherial YAG laser iridotomy, 25 phakic eyes of 25 patients with a history of acute-angle-closure glaucoma (AACG) in the fellow eye. Both plane and polynomial modes of reconstruction of the iridocorneal angle measurement were analyzed. Biometric measurements of the three groups were compared. Biometric measurements (i.e., iridocorneal angle, anterior chamber depth, axial length, and lens thickness) and subjective spherical equivalent were correlated with the etiological classification. Results: Age, sex, iridocorneal angle, anterior chamber depth, lens thickness, axial length and subjective spherical equivalent were significantly different in the three groups (p<0.002). The polynomial iridocorneal angle measurement was 43.4degrees in the normal group, 36.5degrees in the iridotomy group, and 28.4degrees in the AACG group (p<0.001). iridocorneal angle measurement correlated with the other biometric measurements (r(s)>0.51, p<0.001) and with the etiological classification (r(s)=0.68; p<0.001). The anterior chamber depth measurement obtained by Orbscan or echography was the best parameter for predicting ACCG (r(s)=0.77; p<0.001). Conclusion: The anterior chamber depth and polynimial iridocorneal angle obtained using the Orbscan device appears to be useful in predicting acute-angle-closure glaucoma.