Date Published: February 7, 2019
Publisher: Public Library of Science
Author(s): Yoon Seop Sim, Jin-Woo Kwon, Donghyun Jee, Jin A. Choi, Seung-Hyun Ko, Chan Kee Park, Andrew Anderson.
The characteristics of the optic nerve head (ONH) in open angle glaucoma (OAG) patients with diabetes have not been reported. This study aimed to characterize the ONH structures and glaucomatous damage in diabetic OAG patients, using age-matched non-diabetic OAG patients and control subjects.
The locations of visual field defects of OAG patients were classified and the prelaminar thickness and lamina cribrosa depth were measured in 64 OAG patients with type 2 diabetes (OAG+DM), 68 OAG patients without diabetes (OAG-DM), and 36 controls. All participants were scanned by spectral domain-optical coherence tomography. The anterior prelaminar depth and lamina cribrosa depth were measured at the center of the reference line (the Bruch’s membrane opening plane). The prelaminar tissue thickness was obtained by subtracting the anterior prelaminar depth from the anterior lamina cribrosa depth.
The visual field defects in the OAG+DM group were more commonly found in the inferior hemifield (P = 0.010), and tended to involve the central visual field compared to the OAG-DM group (P = 0.044). In the comparison of ONH parameters, the prelaminar thickness was highest in the OAG+DM group, followed by the control subjects and the OAG-DM group (P = 0.035). Post-hoc testing showed that prelaminar thickness was significantly greater in the OAG+DM group than in the OAG-DM group (P = 0.033). The lamina cribrosa depth was deepest in the OAG+DM group, followed by the OAG-DM group and the control subjects (P = 0.006).
Diabetic and non-diabetic OAG patients exhibit different characteristics of glaucoma, particularly increased prelaminar thickening in diabetics.
Diabetes is associated with many ocular complications. Although diabetic retinopathy (DR) is the most well-known complication of diabetes, patients with diabetes may have other ocular complications such as cataract, corneal disease, glaucoma and optic disc abnormalities such as anterior ischemic optic neuropathy, and diabetic papillopathy.
A total of 333 patients with diabetes received an ophthalmic examination between July 2014 and July 2015. Among them, 134 patients having normal optic disc with or without RNFL defect were excluded. Among them, 80 were excluded due to absence of glaucomatous VF defect, 30 were excluded due to presence of PDR or macula edema, and 25 were excluded because of poor EDI images. Finally, 64 OAG+DM patients, 68 age-matched OAG-DM patients, and 36 healthy control subjects were included in this study. There were no statistically significant differences in age, SE, IOP, and central corneal thickness (CCT) among the groups (P = 0.806, 0.486, 0.185, and 0.275, respectively). The average duration of diabetes in the OAG+DM group was 11.3 ± 8.2 years. The OAG+DM group included 39 (60.9%) patients with no DR, 16 (25.0%) with mild NPDR, and 9 (14.1%) with moderate NPDR. No patients in this group had PDR. The interobserver ICC for measuring the prelaminar tissue thickness, laminar cribrosa depth and laminar cribrosa thickness were 0.894 (95% confidence interval (CI): 0.725, 0.959), 0.827 (95% CI, 0.573, 0.930), and 873 (95% CI, 0.670, 0.951), respectively. And the intraobserver ICC for measuring the prelaminar tissue thickness, laminar cribrosa depth and laminar cribrosa thickness were 0.910 (95% CI, 0.846, 0.948), 0.995 (95% CI, 0.993, 0.996), and 0.962 (95% CI, 0.934, 0.978), respectively.
OAG patients with type 2 diabetes tended to have a glaucomatous VF defect in the inferior hemifield, and glaucomatous RNFL damage at the superior side of the ONH (Tables 2 and 3). Our results are consistent with previous studies that have found that OAG patients with inferior VF defects have a significantly higher frequency of diabetes and vice versa.