Detection of the anterior segment configuration of primary angle-closure glaucoma by anterior segment optical coherence tomography

Abstract

To quantitatively measure and evaluate the ocular anterior segment parameters in different subtypes of primary angle-closure glaucoma (PACG) using anterior segment optical coherence tomography (AS-OCT). This retrospective study collected Fifty-five subjects (55 eyes) with APACG, 63 (63 eyes) with chronic primary angle-closure glaucoma (CPACG) and 90 (90 eyes) normal controls from December 2009 to December 2010 in Zhongshan Ophthalmic Center. AS-OCT examination was performed on all patients and the anterior segment parameters were recorded including: central anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber volume (ACV), angle opening distance (AOD), trabecular iris area (TISA), angle recess area (ARA), lens thickness (LT) and crystalline lens rise (CLR). The differences of parameters between APACG, CPACG and normal controls were compared. The anterior segment parameters of APACG and CPACG were significantly (P ≤ 0.001) smaller, respectively, than those of normal controls (PACG: ACD 1.81 ± 0.25 mm, ACW 11.30 ± 0.43 mm, AOD 0.039 mm, ARA 0.038 mm(2), ACV 72.8 ± 16.04 mm(3), TISA 0.017 mm(2), Mean ± SD, and CPACG: ACD 2.02 ± 0.25, ACW 11.49 ± 0.45, AOD 0.042, ARA 0.053, ACV 83.60 ± 19.49, TISA 0.022 vs. normal: ACD 2.70 ± 0.35, ACW 11.81 ± 0.47, AOD 0.260, ARA 0.197, ACV 148.52 ± 31.89, TISA 0.100). The LT and CLR of PACG were significantly (P < 0.001) larger, respectively, than that of normal controls (LT: APACG 5.22 ± 0.38, CPACG 5.06 ± 0.36 mm, CLR: APACG 1.07 ± 0.26, CPACG 0.94 ± 0.21 mm vs. normal: LT 4.57 ± 0.42, CLR 0.39 ± 0.33 mm). Compared with CPACG, the anterior segment parameters of APACG were significantly (P < 0.001 - 0.015) decreased, but the LT (P = 0.003) and CLR were significantly (P < 0.001) increased. Compared with APACG-fellow eyes, the anterior segment parameters of APACG-attacked eyes were significantly (P < 0.001 - 0.041) decreased (Fellow-eye: ACD 1.90 ± 0.23 mm, AOD 0.045 mm, TISA 0.037 mm(2), ARA 0.047 mm(2) vs. attached-eye: ACD 1.81 ± 0.25, AOD 0.039, TISA 0.017 and ARA 0.038), while CLR was significantly (t = 1.349, P = 0.043) increased (fellow-eye: 1.01 ± 0.23 mm vs. Attached-eye: 1.07 ± 0.26). There was no significant difference in the other AS-OCT parameters between APACG-attacked eyes and fellow eyes (t = 0.574 - 1.147, P = 0.257 - 0.567). Our results indicated a more crowding anterior segment configuration in PACG than that in normal controls and a more anterior located and thicker lensing APACG than that in CPACG, which constitute a morphological basis of acute attack.