Assessment of Open-Angle Glaucoma Peripapillary and Macular Choroidal Thickness Using Swept-Source Optical Coherence Tomography (SS-OCT)

OBJECTIVE: To compare peripapillary and macular choroidal thickness (PCT and MCT) between open-angle glaucoma (OAG) and normal controls using swept-source optical coherence tomography (SS-OCT), and to evaluate global and localized relationships between choroidal thickness and various factors in OAG, also using SS-OCT. METHODS: In this cross-sectional comparative study, 134 OAG patients and 73 normal controls were examined. PCT (global, 12 clock-hour sectors), MCT (global, six sectors) were measured by SS-OCT. The difference in choroidal thickness between the OAG patients and the normal controls was analyzed. The relationships between choroidal thickness and various factors including age, sex, spherical equivalent (SE), axial length (AXL), central corneal thickness (CCT), intraocular pressure (IOP), peripapillary retinal nerve fiber layer thickness (pRNFLT), visual field mean deviation (MD), ganglion cell-inner plexiform layer thickness (GCIPLT), and disc area were analyzed by univariate and multivariate linear regression. Global and regional analyses were performed in 12 segments of the peripapillary circle and in six sectors of the macula. RESULTS: There were significant differences in global PCT and MCT between the OAG patients and the normal controls (115.22±41.17 vs. 138.89±44.70, P<0.001), (184.36±57.15 vs. 209.25±61.11, P = 0.004). The difference in global PCT remained, both after adjusting for age, AXL (117.08±3.45 vs. 135.47±4.70, P = 0.002) and also after adjusting for age, AXL, disc area (117.46±3.46 vs. 135.67±4.67, P = 0.002). But the difference in global MCT did not remain after adjusting for age, AXL, SE (188.18±4.46 vs. 202.25±6.08, P = 0.066). PCT showed significant differences between the groups in all of the 12 clock-hour sectors. These differences remained after adjusting for age, AXL and for age, AXL, disc area, with the exception of the 10 o’clock (o/c) sector. MCT in six sectors showed differences between the two groups, but they did not remain after adjusting for age, AXL, SE. In a multivariate regression analysis of the OAG patients, global PCT showed correlations with age (β = -1.18, P = 0.001), AXL (β = -14.01, P<0.001), and disc area (β = -16.67, P = 0.026). Global MCT, meanwhile, showed a significant correlation with age (β = -1.92, P<0.001), AXL. (β = -21.97, P<0.001). Choroidal thickness did not show any global or localized relationship with glaucoma severity in the OAG patients. CONCLUSIONS: The global and all 12 clock-hour PCT, with the exception of the 10 o/c sector, were thinner in OAG; however, they did not show any correlation with glaucoma severity. Possible roles of PCT in glaucoma pathogenesis should be investigated further.