Comparison of swept source anterior segment optical coherence tomography and ultrasound biomicroscopy in measurement of anterior chamber depth and anterior chamber angle data in age-related cataract patients

Abstract

Objective: To explore the difference and agreement in the measurement of anterior chamber depth (ACD) and anterior chamber angle data in age-related cataract patients between swept source anterior segment optical coherence tomography (SS-AS-OCT) and ultrasound biomicroscopy (UBM). Methods: A prospective study. Forty-five eyes from 45 age-related cataract patients were selected at Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University from November to December 2016. There were 23 males and 22 females aged (51±19) years. SS-AS-OCT and UBM were used to measure the ACD, angle opening distance (AOD 500) and trabecular-iris angle (TIA 500). The paired samples t-test and Pearson linear correlation were used for statistical analysis, and the Bland-Altman analysis was used to evaluate the measurement consistency of the two tools. Results: The ACD measured by SS-AS-OCT and UBM was (2.750±0.544) mm and (2.775±0.531) mm, respectively, the difference was statistically significant (t=2.109, P=0.040), and the measurement results were positively correlated (r=0.989, P<0.001). In the nasal, temporal, upper and lower positions, the AOD 500 and TIA 500 values measured by SS-AS-OCT and UBM had a significant difference [AOD 500: (0.451±0.201) mm vs.(0.421±0.194) mm, (0.499±0.229) mm vs. (0.465±0.207) mm, (0.390±0.215) mm vs. (0.355±0.208) mm, (0.441±0.226) mm vs. (0.423±0.215) mm, t=4.262, 4.350, 5.355, 4.415; TIA 500: 39.587°±14.698°vs. 36.944°±13.790°, 42.149°±14.138°vs. 40.289°±13.041°, 36.482°±15.887°vs. 35.600°±15.215°, 38.504°±14.805°vs. 36.818°±14.931°, t=5.131, 4.658, 4.174, 5.731; all P<0.001] and a significant linear correlation (AOD 500: r=0.971, 0.975, 0.979, 0.973; TIA 500: r=0.972, 0.957, 0.956, 0.970; all P<0.001). The Bland-Altman method showed that the two modalities had comparable results for the ACD, AOD 500 and TIA 500 (2.22%-6.67% of the measured value outside the 95% consistency boundaries). Conclusion: SS-OCT and UBM show a good agreement in the measurement of ACD and anterior chamber angle data in age-related cataract patients, though there is difference between them in measurement results. (Chin J Ophthalmol, 2018, 54: 678-682).