[Neurodegenerative changes of the retina in patients with diabetes]

[Multifocal analysis of the bioelectric potential and light sensitivity of the retina in thrombotic microangiopathy associated with malignant arterial hypertension]

PURPOSE

This study evaluates the function of the retina according to multifocal electroretinography (mfERG) and its light sensitivity according to microperimetry (MP) in patients with thrombotic microangiopathy (TMA) associated with malignant hypertension (MH).

MATERIAL AND METHODS

The study analyzed mfERG and MP data of 20 patients (40 eyes) aged 40.4±7.4 years (18 men, 2 women) with MH-associated TMA. In all patients TMA of the kidneys was verified by nephrobiopsy. The control group consisted of 20 healthy individuals (40 eyes) of the appropriate age.

RESULTS AND DISCUSSION

A statistically significant decrease in the response density of P1 mfERG (nV/deg²) of the central retinal zone (0-27.7°) was found in study patients in comparison with the control group (p<0.05), differences in the latency of P1 mfERG (ms) were statistically insignificant (p>0.05). Analysis of MP data in study patients revealed a statistically significant decrease in the mean light sensitivity (dB) of the central field of vision (30°) (p<0.05) compared to the control group. A statistically significant correlation was found between the response density of P1 mfERG (nV/deg²) and mean light sensitivity (dB) in the corresponding quadrants of the visual field (p<0.05). A number of statistically significant correlations were found between the indicators of MP and mfERG and some non-ocular clinical manifestations of TMA in MH.

CONCLUSION

A statistically significant decrease in the light sensitivity of the central field of vision caused by marked decrease in retinal function, probably of an ischemic nature, is characteristic for MH-associated TMA. In this disease the response density of P1 mfERG (nV/deg²) is a sensitive indicator of impaired retinal function. With the activation of systemic TMA, increase in blood pressure and deterioration of kidney function in MH, the light sensitivity of the eye also decreases.

[Multifocal electroretinography in assessment of the functional state of the central retina in patients with retinitis pigmentosa]

Retinitis pigmentosa (RP) is an inherited disease associated with various genetic mutations. Developments in the field of genetic engineering give relevance to the search for methods of studying retinal function, which can prove informative in the selection of patients for treatment.

PURPOSE

To evaluate the information content of multifocal electroretinography (mfERG) in the diagnostics of the functional state of the central retina in retinitis pigmentosa (RP).

MATERIAL AND METHODS

The study included 115 patients (228 eyes) with PR and 15 people (30 eyes) who comprised the control group. All subjects underwent standard ophthalmological examination, computer perimetry, color vision study, retinal spectral optical coherence tomography, ganzfeld electroretinography (gERG) and mfERG. The relationship between mfERG parameters and the degree of gERG changes, as well as various functional and morphological parameters of the retina was assessed.

RESULTS

Visual acuity and perimetry indices varied over a wide range. GERG was unrecordable in 50.4% of cases. MfERG was registered in 214 (98.3%) eyes with varying degrees of change in visual acuity, visual field and gERG parameters. A medium degree positive relationship was revealed between the biopotential density of the retina in the foveal and parafoveal zones and visual acuity (r_s=0.68; 0.63), a high degree - between the density of ttotal biopotential of the central retina (DValue) and the average light sensitivity (r_s=0.9), a weak degree - between DValue and the thickness and volume of the peripheral retina (r_s=0.37; 0.42), a medium negative correlation was found between the average defect in light sensitivity and the biopotential density in the periphery (Rings 4-5) on mfERG, DValue (r_s= -0.67; -0.65; -0.69).

CONCLUSION

MfERG detects retinal dysfunctions at an early stage of RP, in eyes with high visual acuity, normal parameters of the central visual field and gERG, as well as in low visual acuity, a pronounced decrease in light sensitivity, unrecordable gERG. MfERG can be informative in the selection of patients with RP for gene therapy.

[Electrophysiological and psychophysical studies in assessment of visual functions in patients with hereditary optic neuropathy]

PURPOSE

To study the capabilities of electrophysiological and psychophysical examination methods for assessment of the functional state of ganglion cells, retina and optic nerve in patients with hereditary optic neuropathy (HON).

MATERIAL AND METHODS

The study included 60 patients (118 eyes) with a genetically confirmed diagnosis of HON. All study patients underwent visual field test (VFT), spectral optical coherence tomography (OCT), flash and pattern visual evoked potentials (VEP) (Flash-VEP, FVEP; Pattern-VEP, PVEP), photopic electroretinography with photonegative response (PhNR) registration and the color vision test. In 24 patients (46 eyes), these parameters were assessed before the start of treatment and one year later. The treatment involved the mitochondria-targeted antioxidant SkQ1 - plastoquinonyl-decyl-triphenylphosphonium bromide (PDTP) in the form of eye drops.

RESULTS

The main PVEP components for 1.0° and 0.3° were registered in 20% and in 14% of patient eyes with HON and high visual functions, respectively. After one year of PDTP use, a significant decrease in P100 peak latency was found only in the group with disease duration of ≤1.5 years as of the time of treatment start (p<0.05). Significant differences were observed in the PhNR amplitude (p<0.004) between patients of the main and the control groups, as well as in the PhNR amplitude between patients with visual acuity of ≤0.1 and ≥0.13 (p<0.01). Patients with high visual functions were found to have a correlation between the PhNR amplitude, GCC thickness and the global loss index (GLV).

CONCLUSION

Along with VFT, OCT and color vision tests, electrophysiological studies are one of the main methods of examining patients with HON. After one year of PDTP use, there was a significant decrease in the FVEP P2 peak latency in the group with a disease duration of ≤1.5 years as of the time of treatment start. The PhNR amplitude in patients with high visual functions was found to correlate with structural changes in the ganglion cell layer and the retinal nerve fiber layer.

[Ocular ischemic changes in thrombotic microangiopathy associated with malignant arterial hypertension (case study)]

The article presents a clinical observation of visual organ damage as an extrarenal manifestation of thrombotic microangiopathy in malignant arterial hypertension with an analysis of structural and functional changes in the eye by modern examination methods. The presence of renal thrombotic microangiopathy was verified by kidney biopsy. Optical coherence tomography was used to determine structural changes in the inner and outer layers of the retina in the form of their disorganization, areas of thickening of the nerve fiber layer, intraretinal inclusions and cysts, alterations of the ellipsoid zone and retinal pigment epithelium. Optical coherence tomography angiography revealed areas of vascular pattern attenuation in the deep and superficial retinal plexuses corresponding to OCT-detected foci of disorganization of the inner retinal layers. Color Doppler imaging showed absence of the diastolic component of the Doppler spectrum with an increase in the peripheral resistance index RI up to 1.0 in the central retinal artery and posterior short ciliary arteries in both eyes. Functional changes observed with multifocal electroretinography and microperimetry corresponded to the structural changes. Taking into account the similarity of microcirculation in the kidneys and the eyes, the probable pathogenetic mechanism underlying the detected structural and functional symptoms of ischemic damage to the visual organ in malignant arterial hypertension is chronic thrombotic microangiopathy. An interdisciplinary approach to studying thrombotic microangiopathy, including those associated with malignant arterial hypertension, using high-tech examination methods can be useful for timely diagnosis and treatment of this pathology.