[Ocular microcirculation after revascularization of the internal carotid artery in the early postoperative period]. / Mikrotsirkulyatsiya glaza posle rekonstruktivnykh operatsii na sonnykh arteriyakh v rannem posleoperatsionnom periode.

Carotid artery stenosis is the most common cause of ischemic stroke and transient ischemic attacks in the population of developed countries. Carotid endarterectomy (CEA) and carotid stenting (CAS) are effective treatments for carotid stenosis. In view of the need to improve the diagnosis of this condition and the anatomical relationship of the internal carotid arteries and vessels of the eye, studying retinal microvasculature has become an urgent problem. The theory suggesting that changes in ocular blood flow parameters may reflect disease status in patients with internal carotid artery (ICA) stenosis requires further investigation. PURPOSE: To study the impact of CEA and CAS interventions on ocular blood flow in patients with clinically significant ICA stenosis in the early postoperative period. MATERIAL AND METHODS: Thirty-two patients with hemodynamically significant stenosis (≥75%) of the left or right ICA were examined using optical coherence tomography angiography (OCT-A) and flowmetry before and after CEA or CAS in order to assess the changes in ocular blood flow parameters. RESULTS: There were no significant differences in hemodynamic parameters in the eyes on the side of the stenotic and non-stenotic ICA before revascularization. In the early postoperative period (3-7 days) in the ipsilateral eyes, there was an increase in blood flow density and vascular density at the level of the superficial and deep plexuses in the macular area (p≤0.05), as well as an increase in the ocular blood flow volume, the level of tolerated intraocular pressure (p≤0.05) and a decrease in intraocular pressure (p≤0.05) bilaterally. In the contralateral eyes, after ICA revascularization there was a partial improvement in microcirculation parameters according to OCT-A (p≤0.05). Peripapillary blood flow density and peripapillary vessel density did not change significantly either on the ipsilateral or the contralateral side. CONCLUSION: In patients with clinically significant ICA stenosis, ICA revascularization by stenting or endarterectomy contributed to an improvement in retinal microcirculation and retrobulbar blood flow in both eyes. OCT-A and flowmetry allow non-invasive assessment of retinal microvessels and retrobulbar blood flow, and the measurements provided by these methods can serve as valuable biomarkers for predicting and monitoring hemodynamic changes in patients who undergo CEA and CAS surgeries.

[Retinal tomography features of thrombotic microangiopathy associated with atypical hemolytic-uremic syndrome]. / Retinotomograficheskie osobennosti tromboticheskoi mikroangiopatii, assotsiirovannoi s atipichnym gemolitiko-uremicheskim sindromom.

OBJECTIVE: To evaluate structural and morphological changes in the retina using optical coherence tomography (OCT) in patients with thrombotic microangiopathy (TMA) associated with atypical hemolytic-uremic syndrome (aHUS). MATERIAL AND METHODS: The study analyzed OCT data of 14 patients (28 eyes) with an established diagnosis of aHUS including such indicators as central retinal thickness (CRT), thickness of the retinal nerve fiver layer (RNFL), ganglion cell layer (GCL), retinal pigment epithelium (RPE), etc. RESULTS: Patients with aHUS were noted to have an increase in CRT, paracentral acute middle maculopathy in the form of a hyperreflective defect primarily of the inner nuclear layer of paracentral localization, as well as disorganization of the RPE, which was observed statistically significantly more often compared to healthy persons (p=0.0001, p=0.001 and p=0.009 respectively). In the subgroup with thrombotic retinopathy (6 people) a statistically significant increase in CRT and peripapillary RNFL was found (p=0.004 and p=0.001) compared to patients without thrombotic retinopathy, as well as the presence of paracentral acute middle maculopathy and transudative macular retinoschisis (p=0.0001 and p=0.004). A statistically significant thinning of the peripapillary RNFL was revealed (p=0.0001) in the subgroup with symptoms of Purtscher-like retinopathy (PLR) found retrospectively (4 people) compared to patients without retrospective PLR symptoms. A statistically significant decrease in CRT was revealed (p=0.018) in the subgroup of patients receiving systemic therapy with eculizumab (5 people) compared with patients not receiving this therapy. Statistically significant correlations were recorded between the studied OCT indicators, laboratory indicators, and the level of systolic blood pressure (p<0.05). CONCLUSION: According to OCT, paracentral acute middle maculopathy is a biomarker of thrombotic retinopathy and the activity of systemic TMA associated with aHUS. Arterial hypertension is an additional aggravating factor in the development of paracentral acute middle maculopathy and transudative macular retinoschisis. Targeted therapy with eculizumab leads to an effective decrease in CRT, which is potentially associated with regression of ischemic edema. The outcome of PLR involves thinning of peripapillary RNFL.

[Changes in ocular hemodynamics in patients recovered from COVID-19]. / Oftal'mogemodinamicheskie narusheniya posle perenesennoi koronavirusnoi infektsii, vyzvannoi virusom SARS-CoV-2.

PURPOSE: To evaluate the severity of hemodynamic changes in the ocular vessels of patients recovered from COVID-19. MATERIAL AND METHODS: The study included 44 patients (88 eyes) aged 28-60 years, among them 24 (54.5%) women and 20 (45.4%) men, with SARS-CoV-2 infection confirmed by PCR no more than 2 months prior to enrollment and with no ophthalmological complaints within 2 months before the disease, as well as 20 healthy volunteers (40 eyes). At the time of the study all patients had a negative PCR result for SARS-CoV-2. The patients were divided into 2 groups. The first group comprised 24 patients who did not take any anticoagulants during the treatment. The second group consisted of 20 patients who received anticoagulants (Rivaroxaban (Xarelto)) at a dosage of 10 mg per day for 1-1.5 months. The maximum systolic (Vs), end-diastolic (Vd) blood flow velocity, as well as resistance index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were measured in all study patients with the ultrasound imaging system VOLUSON E8 Expert («Kretz¼, USA). Additionally, the flowmetry method was used to assess the volumetric ocular blood flow (VOBF) on Ocular Blood Flow Analyzer system («Paradigm Medical Industries, Inc.¼, USA). RESULTS: In the first group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA and SPCA, as well as an increase of RI in OA compared with the age-normal values (p<0.05). In the second group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA, as well as a decrease in Vs in SPCA and an increase of RI in OA relative to the age-normal values (p<0.05). A decrease in VOBF was noted in the first group in comparison to the second group and the age norm (p<0.05). CONCLUSION: Blood flow velocity parameters in the ocular vessels are reduced in patients recovered from COVID-19 compared to the age-normal values. There was a significant decrease in volumetric ocular blood flow parameters in COVID-19 patients who did not take any anticoagulants compared to the age-normal values. Anticoagulants intake has a positive impact on hemodynamic characteristics in the ocular vessels and volumetric ocular blood flow in patients with COVID-19.

[Ophthalmological manifestations of post-COVID-19 syndrome]. / Oftal'mologicheskie proyavleniya postkovidnogo sindroma.

The review presents data on damage to the organ of vision in patients recovered from the new coronavirus infection reflecting on the results obtained by various researchers from examining patients with varying severity of the disease, both during the active stage and after recovery. Possible ways of transmission of the infectious agent into the organ of vision were analyzed. The most common ocular manifestation of COVID-19 is conjunctivitis, while lesions of the retina and optic nerve were noted less often. The article also outlines the strategy for treatment and describes infection prevention measures for doctors and patients.

[Morphological and functional features of bilateral avascular retinal pigment epithelium detachment (a case report)]. / Morfofunktsional'nye osobennosti bilateral'noi avaskulyarnoi otsloiki pigmentnogo epiteliya setchatki (klinicheskoe nablyudenie).

Detachment of the retinal pigment epithelium (RPE) is a manifestation of a number of degenerative, vascular, inflammatory processes in the eye. The most common cause of RPE detachment in older individuals is the neovascular form of age-related macular degeneration (AMD). Only in 10% of cases the detachment is transudative (avascular), characterized by high domed serous RPE detachment. The article presents an analysis of a case of idiopathic bilateral avascular pigment epithelium detachment - clinical, morphological and functional features of the disease, its impact on the visual functions and the quality of life.

[Ocular thrombotic microangiopathy in atypical hemolytic-uremic syndrome (a clinical case study)]. / Tromboticheskaia mikroangiopatiia glaza pri atipichnom gemolitiko-uremicheskom sindrome (klinicheskoe nabliudenie).

The article presents a clinical observation of ocular thrombotic microangiopathy in atypical hemolytic-uremic syndrome - a rare genetic disease characterized by systemic thrombosis caused by uncontrolled activation of alternative complement pathway. A typical manifestation of this ocular lesion in this disease is bilateral Purtscher-like retinopathy. Timely diagnostics of atypical hemolytic-uremic syndrome, including ophthalmologic examination, determines the early start of a highly effective pathogenetic therapy with complement inhibitor eculizumab.

[Dynamics of electrophysiological parameters of the retina after surgical treatment of idiopathic macular hole]. / Dinamika élektrofiziologicheskikh parametrov setchatki posle khirurgicheskogo lecheniia idiopaticheskogo makuliarnogo otverstiia.

AIM: to study the dynamics of recovery of electrophysiological parameters of the retina after surgical treatment of idiopathic macular hole (IMH) and to assess their relevance to functional prognosis of the operation. MATERIAL AND METHODS: The study included 118 patients (120 eyes) examined before and after successful IMH surgery. The patients underwent electroretinography (Ganzfeld and multifocal), static computed perimetry, and optical coherence tomography. They were also tested for the electrical sensitivity of the retina, lability of the visual analyzer, and critical fusion frequency. Postoperative functional parameters of the retina (electrophysiological included) were followed up at 1-2, 5-6, and 12-plus months and then compared to those obtained before surgery. Parameter dynamics, relationships, and the prognostic value of particular indicators were of interest. RESULTS: It was found that after successful restoration of retinal anatomy, functional parameters of the retina gradually improve and reach their maximum at 3 to 12 months, however, remain below the normal range in all cases. In 58 cases, postoperative visual acuity was 0.5 or higher (regarded as 'high postoperative visual acuity' - the HPVA group) and was accompanied by high density of foveal biopotential and foveal light sensitivity. In the HPVA group, the majority (62%) were patients with preoperative 'shift phenomenon' (a shift of the maximum of bioelectric potential from the fovea to parafovea and perifovea, its amplitude and density being supernormal for these retinal regions). CONCLUSION: Changes in electrophysiological and other functional parameters of the retina can be detected within 3-12 months after successful IMH surgery. Their recovery is not full and goes with a delay relative to restoration of retinal structure. The probability of high functional result of the operation, which includes an increase in visual acuity, foveal light sensitivity, and amplitude and density of foveal biopotential, is higher in patients with biopotential shift at baseline.

[Intraocular pressure, ocular blood flow, and corneal biomechanics changes after LASIK surgery for myopia]. / Vliyanie operatsii LASIK pri miopii na pokazateli oftal'motonusa, ob''emnogo glaznogo krovotoka i «biomekhaniki¼ rogovitsy.

AIM: to study changes in intraocular pressure (IOP), volumetric ocular blood flow (OBF) rate, and biomechanical properties of the cornea after excimer laser ablation in patients with myopia of different degrees. MATERIAL AND METHODS: A total of 16 patients (32 eyes) with myopia ranging from 2.75 to 9.0 D were examined before and after LASIK. Ocular Blood Flow Analyzer (OBFA) was used to measure IOP and OBF as well as pulse amplitude and volume. Ocular Response Analyzer (ORA) was also employed to provide the following data: Goldmann-equivalent IOP, corneal compensated IOP, corneal hysteresis, and corneal resistance factor. The eyes were then divided into two groups: group 1 - 15 eyes with less than 70-µm deep ablation of the cornea and group 2 - 17 eyes with more than 70-µm deep ablation. RESULTS: Group 1 demonstrated a statistically reliable decrease in IOP values provided by either method and biomechanical parameters of the cornea (p<0.005), but no difference in pre- and postoperative OBF, or pulse amplitude, or pulse volume (p>0.05). In group 2, all the parameters changed reliably, except for the pulse volume (p>0.05). In particular, a decrease was recorded for IOP (with no dependence to the method of measurement; p<0.001), pulse amplitude (p<0.01), corneal hysteresis (p<0.001), and corneal resistance factor (p<0.001); an increase - for OBF (p<0.05). CONCLUSION: One should allow for possible mismeasurement of IOP and OBF as well as biomechanical parameters of the cornea in post-LASIK patients, keeping in mind that the extent of error depends on the depth of ablation. Shallow ablation (no more than 70-µm deep) has no statistically significant effect on OBF readings, while IOP seems to decrease considerably. In deep ablation (more than 70-µm deep), both parameters are reliably lower than at baseline.

[Electrophysiological parameters of the retina in idiopathic macular hole]. / Elektrofiziologicheskie pokazateli setchatki pri idiopaticheskom makulyarnom otverstii.

AIM: To investigate the nature and range of electrophysiological disturbances in idiopathic macular hole (IMH) and establish their relationship with structural parameters of the retina. MATERIAL AND METHODS: The study included 249 patients (280 eyes) with IMH. All of them underwent ganzfeld and multifocal electroretinography (ERG), optical coherence tomography, and evaluation of retinal electrical sensitivity and analyzer lability. The results were then compared to those of non-IMH patients (196 paired eyes) and controls (25 people, 49 eyes). RESULTS: Multifocal ERG findings prove that IMH is always associated with significant changes in bioelectrical potential of the central retina. In 62% of cases its decreased density and extended latency were registered in not only the fovea, but also the para- and perifovea. In 8% of cases the changes involved everything within a 30-degree area of the central retina. In 30% of cases the maximum bioelectric potential was found to have shifted from the centre to para- and perifovea, its amplitude and density being supernormal for these regions (shift phenomenon). A weak correlation between electrophysiological parameters and retinal thickness around the hole has been also established. CONCLUSION: Of all methods used to assess retinal function in IMH, multifocal ERG is the most informative. In 100% of cases foveal biopotential is sharply reduced in density and disfigured. In 70% of cases these changes spread outside the fovea.

[Tomography findings in optic nerve head and retina in differential diagnosis between normal-tension glaucoma and ischemic optic neuropathies].

AIM: to determine tomography findings in optic nerve head (ONH) and retinal nerve fiber layer (RFNL) that may be valuable for differential diagnosis between normal-tension glaucoma (NTG) and ischemic optic neuropathy (ION) outcome. MATERIAL AND METHODS: Group 1 consisted of 17 patients (32 eyes) with NTG, group 2--17 patients (24 eyes) with ION outcome. The control group included 22 patients (22 eyes) with no sighs of optic neuropathy. Optic nerve head and retina assessment included scanning laser ophthalmoscopy (HRT 111) and optical coherence tomography (Stratus OCT 3000). Statistical analyses were performed using Statistica 10 software suite. RESULTS: Statistically significant changes in HRT parameters, namely, the mean RNFL thickness, retinal height variation along the contour line, and RB discriminant function, were observed in both study groups as compared to the controls. NTG patients also showed lower rim indices, larger cups, smaller values of the FSM discriminant function, and lower GPS (glaucoma probability score) than both ION patients and the controls. OCT findings included a statistically significant decrease in RNFL thickness in both study groups as compared to the controls. As for the difference between the groups, it was unreliable. Quadrant comparisons of RNFL thicknesses revealed that lower quadrant RNFL thinning was more significant in NTG patients, while temporal quadrant RNFL thinning--in ION patients. CONCLUSION: Both conditions are associated with a similar degree of RNFL thinning, as confirmed by OCT, however, HRT changes are much more pronounced in NTG than in ION patients.

[Effects of blood flow properties on ocular hemodynamics].

AIM: to study the effects of blood rheology on ocular blood flow (OBF) parameters and estimated individual normal range of intraocular pressure (IOP). MATERIAL AND METHODS: A total of 15 patients (15 eyes) taking warfarin were enrolled. Volumetric parameters and linear velocity of OBF under warfarin treatment and after its cessation were obtained by means of flowmetry (Paradigm's Blood Flow Analyzer) and color Doppler flow mapping (Voluson 730), respectively. On the basis of flowmetry results an individual normal range of IOP was calculated in all patients. RESULTS: Pulsatile OBF does not appear to correlate with warfarin-induced changes in blood rheology (p = 0.09), however, depends on IOP fluctuations (p = 0.02). Resistance index of retinal vessels is found to rise significantly with increasing blood viscosity (p < 0.05). CONCLUSION: The use of warfarin, an indirect thrombin inhibitor, has no effect on estimated individual normal range of IOP, which is crucial for glaucoma diagnosis and monitoring.

[Ocular blood flow and carotid artery malfunction].

AIM: to evaluate ocular hemodynamics and informativity of estimated individual normal range of intraocular pressure (IOP). MATERIALS AND METHODS: A total of 12 patients (22 eyes) with carotid artery malfunction were examined. Ocular blood flow (OBF) and IOP were measured with Ocular Blood Flow Analyzer. Actual OBF was then compared with what is considered normal for a given axial length (AL). Individual normal range of IOP was calculated according to an original formula (described in previous publications). Doppler imaging of ocular vessels enabled blood flow velocity measurement. Morphological parameters and functional status of the retina and optic nerve were judged on automated perimetry (Octopus 900) and optical coherence tomography (Cirrus HD-OCT) findings. Statistical analyses were performed using Statistica 10 software. RESULTS: Generally, OBF showed no correlation with the grade of carotid artery stenosis (p < 0.05), however, was significantly reduced as compared to its AL-dependent norm in patients with greater than 85% narrowing of the internal carotid artery, which can cause misestimating of their individual normal range of IOP. A negative relationship was established between the blood flow velocity in short posterior ciliary arteries and the grade of internal carotid artery stenosis (p < 0.005). Ocular blood flow deficit relative to the AL-dependent norm correlated with ophthalmic artery resistance index. CONCLUSION: OBF-based estimation of individual normal range of IOP is inexpedient in patients with greater than 80% carotid artery stenosis due to its possible influence on ocular hemodynamics. In most cases of less than 80% carotid artery stenosis OBF is adequate or slightly reduced as compared to its AL-dependent norm and thus, has no significant impact on estimated individual normal range of IOP.