Relationship between the Lamina Cribrosa, Outer Retina, and Choroidal Thickness as Assessed Using Spectral Domain Optical Coherence Tomography

PURPOSE To evaluate the characteristics and relationship between peripapillary choroidal thickness (pCT), lamina cribrosa thickness (LCT), and peripapillary outer retinal layer thickness (pORT) as determined using spectral domain optical coherence tomography (SD-OCT) enhanced depth imaging (EDI). METHODS In total, 255 participants were included (87 healthy subjects, 87 glaucoma suspects (GS), and 81 glaucoma cases). The pORT, defined as the thickness between the posterior outer plexiform layer and the retinal pigment epithelium (RPE) interface, and the pCT, between the outer margin of the RPE and the choroidal-scleral interface, were manually measured using EDI scanning of the circumpapillary retinal nerve fiber layer (RNFL). LCT was determined by EDI scanning of the optic nerve head (ONH). Baseline characteristics, including axial length (AXL) and the SD-OCT measurements of the participants, were compared among the three groups. The correlation between putative factors and pCT was determined using univariate and multivariate linear regression analyses. RESULTS In all three groups, both pORT and pCT were thinnest in the inferior area among the four quadrants. In the healthy group, the mean peripapillary RNFL, pORT, and LCT were significantly greater in comparison with those of the GS and glaucoma groups (p < 0.001, p < 0.038, and p < 0.001, respectively). The pCT demonstrated no significant differences among the three groups (p = 0.083). Only age and AXL were associated with pCT by multivariate analysis. CONCLUSIONS The pCT is substantially thinner in the inferior area of the ONH. In addition, the pCT demonstrates the strongest correlation with age and AXL, but was not associated with glaucoma or LCT.