ABSTRACT
PURPOSE: To investigate the morphological and functional state of the outer and inner layers of the retina in patients with diabetes mellitus (DM) and nonproliferative diabetic retinopathy (NPDR), to determine the presence and nature of the relationships between structural and functional changes. MATERIAL AND METHODS: The study included 50 patients with subcompensated diabetes and NPDR and 40 people from the control group (healthy). All patients underwent OCT of the retina and optic nerve using RTVue-100 apparatus (Optovue, USA), as well as multifocal electroretinography (mfERG) and pattern electroretinography (PERG) on EP-1000 Multifocal device ('Tomey GmbH', Germany). RESULTS: When analyzing the results of OCT in patients with NPDR, a decrease in the total thickness of the retina and the thickness of its inner layers in the fovea and parafovea regions was found in comparison with the control group (p<0.001), thinning of the retinal ganglion cell (GCS) complex with increased focal losses (FLV) of up to 1.4% (Mann-Whitney test, p=0.001). In the group of patients with diabetes, there was a statistically significant decrease in the density and amplitude of P1 mfERG in all five 'rings' (Mann-Whitney test, p<0.001), increase in implicit time in the first 3 rings, decrease in P50 and N95 amplitude, increase in implicit time of N95 PERG (p=0.001) compared to the control group. CONCLUSION: The study revealed changes in the structure and functioning of the outer and inner layers of the retina in patients with NPDR, and established a reliable correlation between the morphological parameters (according to the OCT) and electrophysiological parameters (according to the mfERG and PERG data).
Subject(s)
Diabetic Retinopathy , Electroretinography , Humans , Retina , Retinal Ganglion Cells , Tomography, Optical CoherenceABSTRACT
Diabetes mellitus is one of the most common chronic diseases in the world. Among its late complications that can lead to disability is diabetic neuropathy (DN). Patients diagnosed with DN often also have diabetic retinopathy (DR). According to available data, DR prevalence ranges from 30 to 60%. For a long time, DR has been considered a microvascular disease. However, more data has been emerging recently that indicates the presence of other components in the pathophysiology of DR. Neurodegenerative changes in the retina can be detected in patients with diabetes mellitus before clinical signs of diabetic retinopathy appear. Accumulation of extracellular glutamate, oxidative stress, reduction of neuroprotective factors synthesized by the retina are all believed to lead to neuronal apoptosis and glial cell dysfunction. This cascade of reactions subsequently causes disruption of the hematoretinal barrier and damage to neurovascular apparatus of the retina. This results in the defeat of capillaries of the retinal vascular system, which is consistently characterized by the loss of pericytes and the formation of unperfusable capillaries. The concept of neurodegeneration being an early component of DR provides an opportunity to explore alternative therapies to prevent the onset of vision loss in diabetes mellitus.
