Predictors of Early Retinal Changes in Diabetes Mellitus

Purpose. Determining the functional state of the outer and inner retina’s layers in patients with diabetes mellitus (DM) type 1 and 2 before the clinical manifestations and in the early stages of diabetic retinopathy (DR) using the methods of multifocal electroretinography (mfERG) and microperimetry (MP).

Patients and methods. 91 patients were examined (182 eyes). The patients were divided into 4 groups: 1st — 23 people (46 eyes) with diabetes without DR (the duration of the disease is up to 2 years); 2nd — 22 people (44 eyes) with diabetes without DR (diabetes from 2 to 8 years); 3rd — 24 people (48 eyes) with NPDR on the background of diabetes; 4th — 22 people (44 eyes) of the control group (healthy eyes). In addition to the standard ophthalmologic examination, all patients were registered mfERG (FOK1) on the diagnostic equipment EP-1000 Multifocal (Tomey, Germany) and carried out MP using the device “MAIA” (CenterVue, Italy).

Results. According to mfERG, it has been established that the components of mfERG, the biopotential density and the amplitude of P1, are most sensitive to diabetic changes. In groups with type 1 and type 2 diabetes, there is a significant decrease in the density of P1 in comparison with the control group (p < 0.005, Mann-Whitney test), as well as a decrease in the amplitude of P1 on almost all tested rings (p < 0.005). In all groups, there is an increase in the latency of P1 in the central ring (0–2.3°). According to MP data, it was found that patients with type 1 and type 2 diabetes showed a decrease in the average light sensitivity in comparison with the control group, however, our data are within the reference values, regardless of the presence or absence of clinical manifestations of PD.

Conclusion. As a result of the study, early functional and morphological disorders of the neurosensory apparatus of the eye in diabetes were identified. It is proved that mfER and MP allow to detect violations at the preclinical stage of DR and are necessary studies for the dynamic control of the progression of DR.

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