Decreased Retinal Ganglion Cell Layer Thickness in Patients with Type 1 Diabetes

Abstract

PURPOSE. To determine which retinal layers are most affected by diabetes and contribute to thinning of the inner retina and to investigate the relationship between retinal layer thickness (LT) and diabetes duration, diabetic retinopathy (DR) status, age, glycosylated hemoglobin (HbA1c), and the sex of the individual, in patients with type 1 diabetes who have no or minimal DR. METHODS. Mean LT was calculated for the individual retinal layers after automated segmentation of spectral domain-optical coherence tomography scans of patients with diabetes and compared with that in control subjects. Multiple linear regression analysis was used to determine the relationship between LT and HbA1c, age, sex, diabetes duration, and DR status. RESULTS. In patients with minimal DR, the mean ganglion cell layer (GCL) in the pericentral area was 5.1 mum thinner (95% confidence interval [CI], 1.1-9.1 mum), and in the peripheral macula, the mean retinal nerve fiber layer (RNFL) was 3.7 mum thinner (95% CI, 1.3-6.1 mum) than in the control subjects. There was a significant linear correlation (R = 0.53, P < 0.01) between GCL thickness and diabetes duration in the pooled group of patients. Multiple linear regression analysis (R = 0.62, P < 0.01) showed that DR status was the most important explanatory variable. CONCLUSIONS. This study demonstrates GCL thinning in the pericentral area and corresponding loss of RNFL thickness in the peripheral macula in patients with type 1 diabetes and no or minimal DR compared with control subjects. These results support the concept that diabetes has an early neurodegenerative effect on the retina, which occurs even though the vascular component of DR is minimal.

Visual sensitivity loss in the central 30° of visual field is associated with diabetic peripheral neuropathy

“…This concentric analysis was designed for the present study to examine whether relative visual sensitivity changes are occurring with increasing distance from central fixation for the neuropathy group. Previously demonstrated diffuse loss of inner retinal integrity using OCT [11,12] supports this approach. A single average dB score is used to represent global, quadrant or concentric ring results.…”

“…Optical coherence tomography (OCT) has enabled high resolution, non-invasive imaging of the complex neural networks within the retina. Several OCT studies have suggested that diffuse neurodegenerative changes may precede the development of clinically visible vascular complications in the retinas of those with diabetes [8][9][10][11][12], and a link between thinning of the retinal nerve fibre layer and DPN has recently been demonstrated [13]. Evidence of retinal structural abnormality reinforces the prospect that visual function may be affected by neurodegenerative changes in diabetes-separate from the better-characterised visual dysfunction attributable to retinopathy [14].…”

Neuroretinal alterations in the early stages of diabetic retinopathy in patients with type 2 diabetes mellitus

“…For example, several studies showed a decreased retinal ganglion cell (RGC) layer thickness in patients with type 1 diabetes. 21 Moreover, in type 2 diabetic patients, neuroretinal alterations are supported both by a retinal function test, electroretinogram or microperimetry, 3,4 and neuroretinal histological evaluation. 22,23 To the best of our knowledge, only a few published studies exist testing GC-IPL and RNFL thicknesses in patients with no signs of DR using an imaging approach.…”

Diabetes enhances the efficacy of AAV2 vectors in the retina: therapeutic effect of AAV2 encoding vasoinhibin and soluble VEGF receptor 1

“…Supporting its safety, the vector did not modify the retinal vascular bed and the ERG in non-diabetic rats. Finally, we explored the thinning of the retina which, owing to the neurodegeneration of the inner retina, occurs in diabetic humans, [42][43][44][45] and in some, [46][47][48][49] but not all, 50 diabetic rodent studies. We confirmed that retinal thinning does not occur at 6 weeks post-STZ-treatment, 47,49 and showed that the AAV2 vasoinhibin vector did not modify it.…”