The Shape of Posterior Sclera as a Biometric Signature in Open-angle Glaucoma: An Intereye Comparison Study.

PURPOSE: To characterize intereye differences in posterior segment parameters and determine their significance in open-angle glaucoma patients with unilateral damage. METHODS: Both eyes from 65 subjects without any nerve damage and 43 patients undergoing treatment for unilateral open-angle glaucoma were included in this study. A 12.0×9.0×2.6 mm volume of the posterior segment in each eye was scanned with swept-source optical coherence tomography. Coronally reconstructed optical coherence tomography images were analyzed to determine the deepest point of the eye (DPE), which we then calculated the distance (Disc-DPE distance), depth (Disc-DPE depth), angle (Disc-DPE angle) from the optic disc center to the DPE. Posterior pole shape was analyzed measuring the posterior pole-cross-sectional area, posterior pole-horizontal width (PP-HW), and posterior pole-vertical width) of the posterior pole. These measurements and their intereye absolute difference (IAD; absolute difference in measurements between the right and left eyes) values were compared between the healthy and unilateral glaucomatous patients. RESULTS: The posterior sclera measurements, including the Disc-DPE distance, Disc-DPE depth, and posterior pole-cross-sectional area, were significantly different between the unilateral glaucoma eyes and contralateral healthy eyes (P=0.043, P=0.035, and P=0.049, respectively). By contrast, none of the intereye differences in optic nerve head parameters were significant in the unilateral glaucoma patients. In comparison with the IAD values, the baseline intraocular pressure and PP-HW of the posterior segment showed significant differences between the healthy and the unilateral glaucoma patients (P=0.019 and P=0.036, respectively). A multivariate analysis showed that a larger baseline intraocular pressure IAD [odds ratio (OR), 1.381; P=0.009)] and larger PP-HW IAD (OR, 1.324; P=0.032) were significantly associated with the presence of glaucoma. CONCLUSIONS: Compared with the fellow healthy eyes, glaucomatous eyes had larger and more steeply curved posterior poles, which represent a structural variation of the posterior sclera that might be associated with glaucomatous optic neuropathy.

Impact of Posterior Sclera on Glaucoma Progression in Treated Myopic Normal-Tension Glaucoma Using Reconstructed Optical Coherence Tomographic Images.

Purpose: To investigate factors associated with visual field (VF) progression in treated myopic normal-tension glaucoma (NTG) using a novel posterior sclera reconstruction method involving swept-source optical coherence tomography (OCT). Methods: Fifty-six myopic patients on ocular hypotensive therapy with the diagnose NTG had five or more VF tests during a period of 72.63 ± 20.46 months in clinical follow-up. Glaucomatous VF progression was decided by the standards of Early Manifest Glaucoma Trial criteria. Coronally reconstructed OCT images were used to obtain the position of the deepest point of the eye (DPE), and parameterized the distance (Disc-DPE distance), depth (Disc-DPE depth) and angle (Disc-DPE angle) of the posterior sclera. The Cox proportional hazards model and Kaplan-Meier curves were used to determine the risk factors for VF progression. Results: Among 56 eyes, 28 showed VF progression. Eyes with progression had significantly different distance, depth, and angle of the DPE position (P = 0.049, P = 0.032, and P = 0.006, respectively). A multivariate Cox proportional hazard model revealed that the vertical tilt angle (hazard ratio [HR] 0.835, P = 0.026) and the DPE positioned temporal to fovea (HR 4.314, P = 0.001) were associated with VF progression. Among eyes with DPE positioned temporal to fovea, in addition to percentage reduction in IOP from baseline (HR 0.915, P = 0.012), shorter axial length (HR 0.542, P = 0.044) was found to be associated with VF progression. Conclusions: Eyes with a particular posterior sclera structure are at increased risk for glaucoma progression in treated myopic NTG patients. This finding highlights the significance of investigating posterior sclera structure and its relevance to initiate or augment treatment for myopic glaucoma patients.