Evaluation of the lamina cribrosa in different stages of diabetic retinopathy.

Abstract

To evaluate the relationship of the peripapillary retina nerve fiber layer (RNFL) and lamina cribrosa (LC) with diabetic retinopathy (DR) in type 2 diabetes mellitus (DM) cases. Prospective comparative study. This study included 50 non-DR (Group 1), 55 non-proliferative diabetic retinopathy (NPDR) (Group 2), 28 DM cases with proliferative diabetic retinopathy (PDR) (Group 3) and 45 healthy volunteers (Group 4). All participants were evaluated with visual acuity, intraocular pressure (IOP) with Goldman applanation tonometry, anterior segment biomicroscopy, 24 - 2 visual field testing, and dilated fundus examination. Retinal nerve fiber layer (RNFL) thickness, lamina cribrosa thickness (LCT) and anterior lamina cribrosa depth (ALCD) were examined by spectral-domain optical coherence tomography (OCT). There was no difference between the groups in terms of age and gender. Visual acuity (p < 0.001) was significantly different between the groups, while IOP (p = 0.068) was similar. Mean (p = 0.010), superior-temporal (p = 0.024), and superior-nasal (p = 0.011) RNFL thickness decreased significantly in correlation with the stage of DR. LCT decreased significantly as the stage of DR progressed in both vertical and horizontal radial OCT scans (p < 0.001). ALCD was not different between groups (p = 0.954 for horizontal scan, p = 0.867 for vertical scan). Peripapillary RNFL and LCT significantly decreases as the DR stage progresses. The biomechanical effects of the LC may also be responsible for diabetes-induced neurodegeneration.