Comparison of the anterior ocular segment measurements using swept-source optical coherent tomography and a scanning peripheral anterior chamber depth analyzer

To compare the anterior ocular segment measurements of two non-contact devices, i.e., anterior segment swept-source optical coherence tomography (SS-OCT) and the scanning peripheral anterior chamber depth analyzer (SPAC), in patients with glaucoma. This was a cross-sectional study of glaucoma patients visiting the Yamanashi University Hospital. The consistency and correlation of various parameters were studied between the SS-OCT and SPAC measurements, including the central corneal thickness (CCT), the central anterior chamber depth (ACD), the trabecular-iris angle (TIA), the angle opening distance (AOD), the area of the recessed angle (ARA), and the trabecular-iris space area (TISA) from the SS-OCT measurements, and the CCT, central ACD, SPAC grade, and SPAC-evaluated anterior chamber angle (ACA) from the SPAC measurements. Seventy right eyes of 70 patients (27 men, 43 women) with glaucoma were enrolled in the study. The mean patient age was 65.9 +/- A 14.5 years. The CCT measurements by SS-OCT and the SPAC were 528.3 +/- A 32.0 and 516.1 +/- A 28.5 mu m, respectively (P < 0.001). The central ACD measurements by SS-OCT and the SPAC were 2.39 +/- A 0.44 and 2.73 +/- A 0.50 mm, respectively (P < 0.001). The two devices showed a significant correlation in terms of the CCT measurements (R (2) = 0.667, P < 0.0001) and the central ACD measurements (R (2) = 0.86, P < 0.0001), but SS-OCT give a significantly shallower central ACD measurement and a thinner CCT measurement compared with the SPAC. AOD, TIA, TISA, and the ARA were all significantly correlated with the SPAC grade and the ACA. Consistency between the two devices was reduced among eyes with primary angle closure. Based on our results, the SS-OCT and SPAC measurements of the anterior segment were significantly correlated, but the values cannot be considered to be directly interchangeable.