Reduced corneal nerve fibre length in prediabetes and type 2 diabetes: The Maastricht Study

n/

Ocular neurodegenerative changes and macular cysts in prediabetes and type 2 diabetes

Over the last 20 years, the number of people suffering from diabetes or prediabetes has doubled. Retinal microvascular changes (i.e. microaneurysms and haemorrhages) and neurodegenerative changes (i.e. degeneration of ganglion cells and axons) are a result of diabetes. These changes can cause vision loss, impaired dark adaptation and colour blindness. Due to diabetes, neurodegenerative changes of the corneal subbasal nerve plexus may occur as well, including reduced nerve fibre length. Therefore, diabetes is associated with delayed corneal epithelial healing, impaired corneal sensitivity and corneal erosions. This dissertation shows that neurodegenerative changes may also occur in the absence of microvascular changes. Approximately 50 percent of neuronal damage of retina, optic nerve and cornea is already present in prediabetes. Early diagnosis of and regular follow-up appointments with people with prediabetes can have a major impact on public health and public health costs

Diabetic retinal neurodegeneration associated with synaptic proteins and functional defects: A systematic review

Diabetic retinopathy (DR) is the most common ophthalmological complication of diabetes mellitus (DM) and a leading cause of preventable visual impairment. In DM, retinal neurodegenerative changes precede microvascular changes which can be assessed by electrophysiological and advanced imaging techniques. Studies measuring retinal neurodegenerative changes in DM were systematically evaluated in this review. Included studies have assessed retinal neurodegeneration in diabetic rodents by combining clinically used diagnostic techniques and molecular assays. Significant impairment was noticed in electrophysiology data in the diabetic retina as compared to the non-diabetic retina. Also, a significant reduction in synaptic protein levels was noticed in the diabetic retina compared to the non-diabetic retina. Even though retinal neurodegeneration was noticed, no vascular abnormalities were seen in the diabetic retina. However, little is known about molecular mechanisms behind diabetic retinal neurodegeneration (DRN), which explains the need for further investigation to detect DR in the early stages of diabetes

Macular thinning in prediabetes or type 2 diabetes without diabetic retinopathy: the Maastricht Study

Purpose: To assess macular thinning in individuals with prediabetes or type 2 diabetes without diabetic retinopathy (DM2 w/o DR) compared with individuals with normal glucose metabolism (NGM). Methods: Using spectral domain optical coherence tomography (SD-OCT), we measured macular thickness in six subfields as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) in 1838 participants from The Maastricht Study, a population-based cohort study (mean age 59 ± 8 years, 49% men, 1087 NGM, 279 prediabetes, 472 DM2 w/o DR). Multivariable linear regression was used to assess the association between macular thickness and glucose metabolism status. Results: After adjustment for age, sex and spherical equivalent, individuals with prediabetes showed a significant decrease in pericentral superior macular thickness [β = −2.14 μm (95% confidence interval (CI): −4.24 to −0.03), p < 0.05] compared with individuals with NGM. In individuals with DM2 w/o DR, the fovea [β = −4.05 μm (95% CI: −6.30 to −1.79), p < 0.001] and the four pericentral quadrants (range: β = −4.64 to −5.29 μm, p < 0.001) were significantly thinner compared with individuals with NGM. There was a significant linear trend of macular thinning with severity of glucose metabolism status in five subfields (p < 0.001). Conclusion: Macular thickness is reduced in prediabetes and a greater reduction occurs in DM2, even before DR is clinically present. About half of the thinning observed in DM2 w/o DR was already found in prediabetes. Generalized thinning of the macula could be related to thinning of the temporal side of the optic nerve head through the connecting papillo-macular bundle