Eye damage in COVID-19. Part 2: posterior segment complications, neuro-ophthalmic manifestations, vaccination and risk factors

Posterior eye segment involvement in COVID-19 has varied manifestations: vascular, inflammatory, and neuronal. All of them are triggered by SARS-CoV-2 virus but they cannot be viewed as exclusively specific to COVID-19. According to the literature, the mean age of the patients varies from 17 to 75 with the median of 50 years. The median duration between the appearance of ophthalmic symptoms and the detection of COVID-19 was 12 days. The disease affects both men and women equally. Direct exposure to the virus, immune-mediated tissue damage, activation of the coagulation system, the prothrombotic state caused by a viral infection, concomitant diseases and medications used in the treatment contribute to the development of eye pathologies. Ophthalmologists should be aware of the possible relations of posterior eye segment pathologies, orbit and neuro-ophthalmic disorders with SARS-CoV-2, as well as the possible exacerbation of chronic forms of inflammatory eye diseases and autoimmune disorders due to anti-COVID-19 vaccination.

[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 1. Study methods, measurement variability and the role of age-related changes]

This paper reviews the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma and considers the significance of evaluating retinal nerve fiber layer and ganglion cell complex in assessment of glaucoma progression, variability and reproducibility of the method, as well as the influence of age-related retinal changes on the results, analyzes the role of OCTA in glaucoma monitoring. Optical coherence tomography is a modern standard for glaucoma diagnosis and monitoring, and OCTA shows high potential as an auxiliary diagnostic tool.

[Late diagnosis of rhinocerebral mucormycosis in patients with COVID-19 (case studies)]

From the beginning of the COVID-19 pandemic, the incidence of secondary infections (both bacterial and fungal) has increased due to immune suppression associated with the use of corticosteroids or broad-spectrum antibiotics as a part of COVID-19 treatment protocol, which may exacerbate a pre-existing fungal disease or cause a new infection. Ophthalmologists are often involved in taking medical and surgical decisions in these complex cases. In this regard, a strong clinical suspicion should be applied to possible secondary fungal infections in COVID-19. Their early diagnosis and treatment may reduce mortality due to COVID-19 associated rhinocerebral mucormycosis (ROCM). This article describes two clinical cases of late detection of ROCM with two different scenarios, and compare the features of these cases with the literature data.

[The value of lamina cribrosa in the diagnosis and treatment of glaucoma. Remodeling of lamina cribrosa collagen and approaches to its therapeutic treatment]

Among the first structures suffering damage with an increase in intraocular pressure (IOP) and in early stage of glaucoma are the lamina cribrosa (LC) and peripapillary sclera (ppScl). Changes in these structures occur at the molecular and cellular level. Extracellular matrix (ECM) is the basis of connective tissue, provides mechanical support for the cells, facilitates intercellular interactions and transport of chemicals, including in LC and ppScl. Mechanical stress causes remodeling and disorganization of the ECM, which leads to changes in the structure of the tissue itself, an increase in its rigidity and a decrease in elasticity. Taking into account the molecular and cellular mechanisms of damage to LC and ppScl, various researchers have developed strategies and tactics for therapeutic intervention on these structures, contributing to a decrease in ECM secretion and, as a consequence, suspension of their remodeling. These approaches may in the future form the basis for the treatment of glaucomatous optic neuropathy.

[Predictors of the success of laser peripheral iridotomy and lensectomy in the early stages of primary angle closure disease]

The article reviews literature data on the search for predictors of the success of laser peripheral iridotomy (LPI) and lensectomy in the early stages of primary angle closure disease (PACD) and presents a trend analysis of the studies conducted on individuals identified as primary angle closure suspects (PACs) and those with primary angle closure (PAC). The concept of the review was determined by the ambiguous choice of treatment for patients at the stage of PAC onset. Determining the success predictors of LPI or lensectomy plays a key role in optimizing the treatment of PACD. The results of literature analysis are contradictory, which indicates the need for further research taking into account modern methods of visualization of the eye structures such as optical coherence tomography (OCT), Swept Source OCT (SS-OCT), and the use of uniform criteria for evaluating the effectiveness of treatment.

[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 2. Clinical and functional correlations, monitoring of advanced glaucoma and limitations of the method]

The purpose of this study is to analyze the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma. This review considers the structural and functional correlations observed during the progression of glaucomatous optic neuropathy, as well as the capabilities of the method in late glaucoma, describes the strengths and weaknesses of OCT and OCTA, and pays particular attention to the role of OCT in assessing the effectiveness of treatment. Optical coherence tomography is the main method for determining the progression of glaucoma, which plays a key role in the choice of treatment algorithm. However, the use of OCT in far advanced glaucoma has certain particularities and limitations. OCTA can be helpful in overcoming this problem.

Eye damage in COVID-19. Part 1: Involvement of the eye in SARS-CoV-2 virus transmission and anterior segment complications

In COVID-19, eye damage may develop at any stage of the disease. Viral ribonucleic acid has been found in ocular tissues, but the role of the eye as a route of infection is yet to be substantiated. Ophthalmic manifestations may be a typical feature of COVID-19 infection or they may develop several weeks after recovery. Ophthalmologists should be aware of possible relationships of an ophthalmic pathology with SARS-CoV-2 in order to obtain targeted case history, detect the specific signs, prescribe the necessary tests and thereby reduce the spread of the infection. These relationships are also important for early diagnosis and treatment of complications that threaten the patients’ life and vision. The first part of the review focuses on the possible involvement of the eye in SARS-CoV-2 infection and the spread of infection. Clinical manifestations of the anterior segment damage are considered.

[Comparative study of retinal microcirculation in primary angle closure disease and early primary open-angle glaucoma]

PURPOSE

To compare microcirculatory changes in patients with early stages of primary angle closure disease (PACD) and primary open-angle glaucoma (POAG).

MATERIAL AND METHODS

The study retrospectively analyzed the clinical data of 60 eyes with PACD, 30 with initial POAG, and 30 eyes without any ophthalmic pathologies. Vessel density (VD) in the optic nerve head and peripapillary retina (wiVD Disc), as well as in the inner layers of fovea and parafovea (wiVD Macula) and their different sectors were determined in all patients by optical coherence tomography angiography (OCTA). The correlation of VD with axial length (AL), anterior chamber depth (ACD), lens thickness (TL), and corneal-compensated intraocular pressure (IOPcc) was assessed.

RESULTS

The wiVD Disc in PACD (42.47±4.23%) was lower than in POAG eyes (47.46±2.10%), p<0.001, but the difference for wiVD Macula was not significant: 41.71±4.55% and 39.29±2.46%, respectively (p=0.47). In both PACD and POAG, all OCTA parameters were lower than in normal eyes: p=0.000 for both wiVD Disc and wiVD Macula. WiVD Disc correlated with ACD both in PACD (r=0.724, p=0.012) and in POAG (r= 0.685, p=0.012), but a correlation with IOPcc was found only in PACD (r= -0.670, p=0.033). The largest number of inverse correlations was found between TL and VD both for wiVD Disc (r= -0.714, p=0.006) and the parameters of macular area (in para- and perifovea).

CONCLUSION

OCTA parameters differ significantly from the norm even in the early stages of both PACD and POAG. In PACD, there was a significant decrease in microcirculation in the peripapillary retina compared to POAG, which had an inverse correlation with IOPcc; there was also an inverse correlation of OCTA parameters in the optic nerve head and macula with lens thickness.

[Primary anterior chamber angle closure: progression from suspect to glaucoma. Part 2. Predictors of primary angle closure]

To review the literature devoted to the search of predictors of primary angle closure (PAC) progression as an important link in the pathogenesis of primary angle-closure glaucoma. This part presents a cluster analysis, describes the mechanisms of PAC development, and considers the studies aimed at discovering the risk factors for the progression of primary angle closure suspect into true angle closure. The results of the analyzed literature are ambiguous, indicating the need for further research that would involve strict inclusion criteria, and a standard approach to defining the primary angle closure disease and expanding the diagnostic parameters, in which a key role belongs to anterior segment optical coherence tomography (AS-OCT).

[Primary anterior chamber angle closure: progression from suspect to glaucoma. Part 1. Frequency and rate of transition from suspected primary angle closure to true angle closure and primary angle closure glaucoma]

To review the literature devoted to the problem of primary anterior chamber angle closure (PAC) and the development of this pathology from glaucoma suspect to primary angle closure glaucoma. The paper includes a trend analysis of the studies concerning primary angle closure suspects (PACS). The concept of this review is conditioned by the conflicting strategies for treating patients with initial PAC without glaucomatous optic neuropathy. Solving the problem of angle closure plays a key role in preventing the development of PAC glaucoma, which is the world's leading cause of irreversible blindness. This part of the review provides information on the frequency and rate of disease progression in PACS. The analyzed literature data is contradictory and indicates the need for further search that would consider a standardized approach to defining the concept of PAC disease, demographic factors and unified examination methods for generalizing and systematizing data in order to draw out unified treatment recommendations.

[Neuroprotective properties of latanoprost]

Glaucoma is the main cause of irreversible blindness in the world. Latanoprost - an ester prodrug of prostaglandin F_2α (PGF_2α) - was the first prostaglandin analogue used to treat glaucoma. The review shows that latanoprost possesses direct neuroprotective properties such as blocking the entry of calcium ions into neurons and inhibiting the action of caspase-3, inhibiting the activity of cyclooxygenase and activation of polypeptide 2B1 (OATP2B1) and Klotho protein. It is emphasized that when the drug is instilled into the eye, the concentration of the drug inside the vitreous body is twice as high as what is required to ensure the survival of retinal ganglion cells.

[Morphology of outer retinal tubulations in the outcome of exudative age-related macular degeneration according to optical coherence tomography angiography]

Outer retinal tubulation (ORT) develops in the later stages of age-related macular degeneration (AMD). It is associated with low visual acuity, severe loss of photoreceptors, choroidal neovascularization (CNV), and geographic atrophy. Despite the frequent detection of ORTs by optical coherence tomography (OCT), their role in the process of outer retinal atrophy and degenerative changes in photoreceptors remains undetermined.

PURPOSE

To investigate the evolution of ORT in patients with exudative and disciform-stage CNV.

MATERIAL AND METHODS

The retrospective study included 340 patients with AMD, among them 235 (69%) women and 105 (31%) men with mean age of 76±7.4 years; in all, the analysis involved 267 eyes with dry AMD and 174 eyes with CNV: 92 eyes - with exudative AMD, 82 eyes - with disciform-stage disease). In addition to standard OCT, all patients underwent OCT-angiography (OCTA). In 10 cases, patients with exudative AMD were followed up after intravitreal injections of Aflibercept.

RESULTS

ORTs were detected in 37 eyes of 32 patients (26%), all of them with CNV: 13 eyes with exudative AMD (group 1) and 24 eyes with disciform scar (group 2; p=0.013).

The groups were similar in the type and morphology of ORTs. The most common were closed, i.e. fully formed ORT (92% of cases in group 1, and 88% in group 2). Destruction of the ellipsoid zone associated with ORT was observed in both groups. In one case, there was an increase in the size of ORT corresponding to the volume of cystic macular edema. Disappearance of ORT was noted only in one of ten patients 3 months after intravitreal injection of Aflibercept, but was not accompanied by visual acuity improvement.

CONCLUSION

Outer retinal tubulations are more common in the later stages of AMD, being an indicator of a deep destructive process in photoreceptors. In exudative AMD, ORTs serve as a predictive marker for poor functional outcomes.

[Providing eye care during the COVID-19 pandemic]

The review presents the data on characteristic features of the new coronavirus infection caused by SARS-CoV-2 and the possibility of its transmission through the eye surface and lacrimal fluid, analyzes the information on eye damage caused by COVID-19, and provides the results of a systematic meta-analysis on the subject. The author describes the system for organizing ophthalmological care in the settings of unfavorable epidemiological situation associated with the COVID-19 pandemic, and considers the preventive measures of infection transmission between patients and medical personnel. The article also gives recommendations for sterilizing medical equipment.

[Examination of patients with glaucoma during the COVID-19 pandemic]

PURPOSE

To evaluate the efficacy of the optimal examination technique for patients with glaucoma during the COVID-19 pandemic that includes one of the safest methods of tonometry [transpalpebral tonometry (TPT), contour dynamic tonometry (CDT) and Icare rebound tonometry (RBT)] in combination with spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA).

MATERIAL AND METHODS

The study included 65 patients with primary open-angle glaucoma (POAG) who sought medical aid at the Ophthalmological Center of FMBA during the COVID-19 pandemic; they were examined using three tonometry methods: RBT, TPT and CDT. All patients underwent central corneal thickness measurement, perimetry, OCT and OCTA with assessment of vessel density (VD) of the superficial plexus in the macula (whole image macula) and peripapillary retina (PPR).

RESULTS

High correlation was found between the results obtained with RBT, TPT and CDT. None of the methods showed a correlation between IOP and corneal thickness. The correlations between IOP and OCTA parameters were obtained: IOP_TPT and VD_PPR in the inferior temporal sector (r= -0.386, p=0.027), IOP_RBT and VD whole image macula (r= -0.69, p=0.019), and in the macula inferior hemisphere (r= -0.75, p=0.008), as well as between the ocular pulse amplitude (OPA) and VD in the macular inferior hemisphere (r=0.380, p=0.039). The OCTA parameters had a moderate, but significant correlation with the perimetric indices.

CONCLUSIONS

Tonometry methods (TPB, CDT and RBT) exhibit high correlation with each other and no correlation with corneal thickness. IOP parameters measured by different methods, especially using the Icare tonometer, correlate with OCTA parameters, and the latter - with perimetric indices. The combination of these tonometry methods with SD-OCT and OCTA is optimal for examining patients during the pandemic.

Optical coherence tomographic patterns in patients with retinal vein occlusion and macular edema treated by ranibizumab: a predictive and personalized approach

Purpose

To establish the morphological and functional parameters to predict the effectiveness of intravitreal injections (IVI) of ranibizumab in macular edema due to retinal vein occlusion and to develop a mathematical model for personalized treatment algorithms.

Material and methods

This is a retrospective study of 98 patients (98 eyes) with macular edema, who received IVI of ranibizumab and were followed up for 12 months. Spectral optical coherence tomography scans and best corrected visual acuity (BCVA) assessments were conducted every 3 months. Treatment outcome predictors were calculated based on logistic regression analysis.

Results

The most significant prognostic factors for the long-term BCVA were baseline BCVA (OR 11.1, p = 0.001), foveal volume (OR 10.8, p = 0.001), destruction of external limiting membrane (OR 15.8, p = 0.001), photoreceptor inner/outer segments (OR 11.1, p = 0.001) and retinal pigment epithelium (OR 9.1, p = 0.001). It has also been discovered that post-treatment BCVA correlated with the height of serous retinal detachment (SRD) (r = -0.4, p = 0.001), ganglion cell complex thickness (r =  + 0.3, p = 0.01) and focal loss of ganglion cells (r =-0.3, p = 0.005). Patients without SRD required fewer ranibizumab injections (3.8 ± 1.1) for macular edema fluid resorption compared to those with SRD (5.7 ± 1.2, p = 0.03). A mathematical model for predicting and personalized approach therapy of ranibizumab has been obtained (accuracy of 89%).

Conclusion

The effectiveness of IVI of ranibizumab depends on baseline morphological and functional changes. The obtained mathematical model allows for predicting the outcomes of therapy, determining individualized algorithms to increase the treatment effectiveness and to prevent low vision that corresponds to the principles of predictive, preventive, and personalized medicine.

[The role of retinal microcirculation disorders in the progression of glaucomatous optic neuropathy]

PURPOSE

To assess the progression of primary open-angle glaucoma (POAG) and to study the role of retinal microcirculation in its progression.

MATERIAL AND METHODS

In this 2-year prospective study, the rate of POAG progression was determined using perimetry (ROP1) and spectral domain optical coherence tomography (SD-OCT) by thinning of retinal nerve fiber layer (RNFL) (ROP2) and ganglion cell complex (GCC) (ROP3). The vessel density of parafoveal superficial plexus (VD parafovea) and peripapillary retina (VD ppr) was assessed using OCT angiography, peripheral resistance index (RI), and blood flow velocity in the posterior short ciliary arteries (PSCA) and central retinal artery (CRA) with the use of color Doppler mapping. The predictive properties of each parameter were calculated using the area under receiver operating curve (AUC).

RESULTS

Progression was detected in 9.8% cases by perimetry and in 19.7% cases by OCT. The combination of these two methods increased the detection up to 32.8%. Circulatory parameters - VD parafovea (AUC 0.70±0.07), VD ppr (0.715±0.07), PSCA RI (0.801±0.12), CRA RI (0.798±0.11) - had similar high predictive properties as IOP max (0.79±0.05), corneal hysteresis (0.755±0.07), thickness of inner parafoveal layers (0.728±0.07) and RNFL (0.692±0.06). The study revealed the following correlations: ROP1 with maximum IOP (p=0.01), ROP2 with blood flow velocity in PSCA (p=0.01), VD parafovea with corneal hysteresis (p=0.01), and GCC thickness with ocular perfusion pressure (p=0.01).

CONCLUSION

The obtained data demonstrates the importance of combining perimetry with OCT for detecting the progression of glaucoma and indicates its relationship with reduced ocular hemoperfusion.

[Comparative study of factors associated with the progression of primary open-angle and angle-closure glaucoma]

PURPOSE

To compare the factors associated with the progression of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).

MATERIAL AND METHODS

This prospective study analyses clinical data of POAG and PACG patients followed up for 6 years. The progression of glaucomatous optic neuropathy (GON) was determined using perimetry and spectral optical coherence tomography (OCT). The value of each diagnostic indicator (z-value) was calculated using the Wilcoxon-Mann-Whitney test and the area under the ROC-curve (AUC) to identify the parameters reliably associated with the progression in both groups of patients.

RESULTS

According to OCT, 47.3% of PACG patients and 52.46% of POAG patients had GON progressing, while according to perimetry, these figures were 21.8% and 23%, respectively. The common factors associated with progression of these glaucoma forms were age (AUC 0.7, z -1.9 in PACG and AUC 0.7, z -2.9 in POAG) and maximum IOP (0.7; -2.7 in PACG and 0.79; -5.4 in POAG). The progression of PACG is associated with lens size (0.7; -2.4), subfoveal choroidal thickness (AUC 0.8, z -3.3) and peripapillary choroidal thickness (0.79; -3.2), resistive index in the vortex veins (0.81; -3.3) and their end diastolic blood flow velocity (0.83; 3.2). The progression of POAG is associated with a thin peripapillary (0.75; 2.6) and subfoveal choroid (0.74; 2.5), increased resistive index in the posterior short ciliary arteries (0.8; -2.3), and initial retinal nerve fiber layer (RNFL) thickness: 0.69; 2.9.

CONCLUSION

The progression of POAG and PACG has only two common factors - age and maximum IOP. The progression of PACG is mainly related to the lens size, venous dysfunction and the choroid expansion, while the progression of POAG is related to the initial RNFL thickness, reduced arterial blood flow and choroid thinning.

[Long-term use of latanoprost in the treatment of glaucoma]

Glaucoma is the main cause of irreversible blindness in the world. Latanoprost - an ester prodrug of prostaglandin F2α (PGF2α) - was the first prostaglandin analogue used in the treatment of glaucoma. The present review shows that latanoprost is the most balanced prostaglandin analogue in terms of efficacy-safety. Its use improves the quality of life of glaucoma patients, provides reliable IOP reduction, has high patient compliance, and helps with the long-term preservation of visual functions. The review also reveals the possibility of long-term (more than five years) use of the drug, as well as effective combined treatment using latanoprost and beta-blockers, considers the pediatric use of latanoprost, and discusses its neuroprotective properties.

[Biomechanical properties of the cornea as predictors of the effectiveness of selective laser trabeculoplasty]

PURPOSE

To study the changes in central corneal thickness (CCT) and corneal hysteresis (CH) after selective laser trabeculoplasty (SLT) in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) after laser peripheral iridotomy (LPI) and to determine their effect on the prognosis of the surgery.

MATERIAL AND METHODS

The prospective study involved 68 eyes with initial PACG after LPI and 74 eyes with initial POAG observed for 6 months. Corneal-compensated IOP (IOPcc), corneal resistance factor (CRF), CH and CCT were studied as the predictors of SLT, which was considered successful when IOPcc decreased by 20% or more from the baseline without additional hypotensive therapy and/or repeated SLT.

RESULTS

In both forms of glaucoma, CCT increased within the first hour after SLT: 567±24.08 µm (p=0.001) in POAG, and 572±21.41 µm (p=0.000) - persisting for over a month - in PACG. CCT correlated with laser energy at all stages of the examination both in POAG and PACG patients. The following predictors of SLT failure were determined: CH (p=0.000 in PACG and p=0.001 in POAG), as well as initial IOP (p=0.010 in PACG and p=0.016 in POAG) and CRF (p=0.003 in PACG and p=0.005 in POAG) and CCT (p=0.023 in PACG and p=0.026 in POAG). The value of anterior chamber angle (ACA) was a predictor only for PACG (p=0.011).

CONCLUSION

SLT leads to an increase in CCT, which lasts longer in PACG after LPI than in POAG and correlates with the level of laser energy. Lower CH and initially higher IOP are the common predictors of SLT failure in the long term for both forms of glaucoma. Smaller ACA have a negative prognostic sign in POAG.

[Selective α2 agonists in the treatment of glaucoma: neuroprotective properties and impact on ocular blood flow]

Glaucoma is the main cause of irreversible blindness in the world. The selective α2 adrenergic receptor agonist brimonidine holds an important place among the hypotensive eye drops. The second part of this review focuses on some important effects of brimonidine that characterizes it as a medication with direct neuroprotective multifactorial action, discusses its influence on ocular blood flow and highlights its capability to maintain normal autoregulation of ocular blood flow.

[Selective α2-agonists in the treatment of glaucoma: pharmacology, efficacy and safety]

Glaucoma is the main cause of irreversible blindness in the world. Among the hypotensive eye drops, an important place belongs to the selective α2-adrenergic receptor antagonist brimonidine. This part of the review focuses on key pharmacological and therapeutic characteristics of brimonidine and its mode of action. The article also discusses the side effects of brimonidine and the methods of their prevention.

[Pattern electroretinogram and macular perfusion in glaucoma]

PURPOSE

To study microcirculatory and functional changes in macula in patients with Primary Open-Angle Glaucoma (POAG).

MATERIAL AND METHODS

The study included 95 POAG patients and 42 healthy control subjects. Whole en face image vessel density (wiVDRetina) was measured both in fovea and in parafovea using OCT-angiography (OCT-A) by means of SD-OCT AngioVue on Avanti RtVue xR (Optovue Inc., U.S.A.). Macular thickness and parameters of macular ganglion cell complex (GCC) were measured on the same day. Blood flow in the retrobulbar vessels was evaluated by means of Color Doppler Imaging (CDI). Pattern electroretinogram (PERG) was also taken from the study eyes. Correlations between PERG, SD-OCT GCC, macular thickness, and the parameters of OCT-A and CDI were studied.

RESULTS

The amplitude of t-PERG P50 decreased from 6.1±1.3 µV in normal eyes to 2.8±1.6 µV (p<0.0001) in early glaucoma and to 2.3±1.5 µV (p=0.93) in advanced stages. Relative vessel density of the capillary bed decreased from 51.3±3.0% in normal eyes to 45.9±5.0% (p<0.001) and to 41.8±5.0% (p=0.023) in early and advanced glaucoma respectively. The parameters of OCT-A and CDI correlated with morphological and functional parameters in normal and early glaucomatous eyes.

CONCLUSION

The study revealed reduction of macular microcirculation and decrease of PERG in early glaucoma. Correlations between the circulatory parameters and functional changes were found in early stages of the disease.

[Macular blood flow in glaucoma]

AIM

to assess macular blood flow in primary open-angle glaucoma (POAG) patients using optical coherence tomography angiography (OCT-A).

MATERIAL AND METHODS

The study included 65 POAG patients and 22 age-matched healthy volunteers. Using OCT-A, blood flow parameters (Flow Area, Flow Index, and Vessel Density) were assessed in the para- and perifovea (0.6-2.5 mm and 2.5-5.5 mm, respectively) at the level of both superficial and deep vascular pexuses. Statistical analysis was performed with SPSS version 21 and MASS library of the R language.

RESULTS

All the studied parameters were decreased in glaucoma patients as compared to healthy participants: Index superficial parafovea was 0.03±0.01 and 0.04±0.01 (p<0.001), respectively; Index superficial perifovea - 0.02±0.01 and 0.04±0.01 (p<0.001), respectively; Flow superficial parafovea area - 1.57±0.85 mm2 and 2.53±0.53 mm2 (p<0.001), respectively; Index deep parafovea - 0.02±0.02 and 0.03±0.01 (p<0.001), respectively; Index deep perifovea - 0.01 ±0.01 and 0,03±0.01 (p<0.001), respectively; and Flow deep parafovea area 1.02±0.9 mm2 and 1.97±0.82 mm2 (p<0.001), respectively. The differences were statistically significant between glaucoma patients and the controls, but not between glaucoma patients at different disease stages.

CONCLUSION

Decreased OCT-A parameters in non-advanced glaucoma indicate an early reduction of blood supply to the macula and explain the involvement of the latter in the pathological process in POAG.

[Pattern visual evoked potentials and their relation to the peripapillary and retrobulbar blood flow in glaucoma]

PURPOSE

To examine the relationship between the development of bioelectric response of retinal cell elements to pattern stimulus and the ocular blood flow.

MATERIAL AND METHODS

Electrophysiological studies, including pattern-reversal visual evoked potentials (VEP) with large 1 degree (1°) and small 0.25° checks, Color Doppler imaging (CDI) of the retrobulbar vessels, and OCT Angiography in the area of the optic disc and peripapillary retina were performed in 48 patients with initial primary open-angle glaucoma (POAG), 47 patients with advanced POAG, and 42 control subjects. Authors also studied the correlations between VEP values and the parameters used in CDI and OCT-A examination.

RESULTS

The most noticeable differences between the study groups were the amplitudes of P100 pattern VEP values for small and large patterns and the OCT-A parameters: Whole-image Disc Vessel Density (widVD), Peripapillary Vessel Density (pVD), Peripapillary Vessel Density Inferior Temporalis (pVD IT). In initial glaucoma, a strong correlation was observed between the amplitude of P100 pattern VEP 1° and pVD IT (r=0.75; p<0.0001); the blood flow rates in ophthalmic artery, central retinal artery, central retinal vein and short posterior ciliary arteries were below normal, while the blood flow in these vessels had statistically reliable correlation with the amplitude of P100 pattern VEP (p<0.05). No correlation was found in patients with advanced stages of glaucoma.

CONCLUSION

Pattern VEP is an informative method of glaucoma diagnostics which accuracy can be enhanced by combining it with OCT-A blood flow examination.

[Optical coherence tomography angiography in glaucoma diagnosis]

According to literature data, vascular dysfunction may well contribute to the development of glaucomatous optic neuropathy, which makes it reasonable to search for new imaging techniques capable of early diagnosis and monitoring of glaucoma through assessment of retinal, optic nerve head (ONH), and choroidal perfusion. Optical coherence tomography angiography (OCTA), a recently introduced method based on the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm, enables evaluation of both retinal and choroidal blood flow in peripapillary and macular areas. The first studies involving OCTA have revealed a decrease in retinal blood flow in glaucoma. It has also been shown that visual field indices correlate better with the peripapillary flow index than with morphometric parameters of the optic nerve head (ONH) and peripapillary retina. OCT angiography has great potential for ONH blood flow assessment during physiological tests, which is an important step towards understanding pathogenesis of glaucoma.

[Use of physiological reparation regulators in glaucoma surgery: a clinicoimmunological study]

The paper presents the comparative results of clinical and immunological studies dealing with the use of the physiological reparation regulators (the human amniotic membrane and systemic enzyme therapy) and the antimetabolite 5-fluorouracil (5-FU) to prevent excessive ocular tissue scarring. The clinical observations have demonstrated the high efficiency of the proposed methods for the physiological regulation of reparative processes as compared with the use of 5-FU, which manifested as a more marked normalization ofophthalmotonus and fewer numbers of postoperative complications. The investigation of the study of proliferation-activating cytokine (TGF-beta1) and antiprolerative cytokine (IFN-gamma) has demonstrated the immunomodulating properties of the physiological reparation regulators used in the present study.

[Nitrogen oxide in the pathogenesis of glaucoma and cataract]

The content of nitrite (final metabolite of nitroradical) was measured in aqueous humor of patients with glaucoma and cataract. The level of NO formation is increased at the initial stage of glaucoma and decreases with the disease progress. A direct correlation between the level of nitrite in aqueous humor and coefficient of easiness of its discharge was detected. Cataract is associated with a high level of nitrite in intraocular fluid. The results are discussed from the viewpoint of ocular hydro--and hemodynamic regulation and NO involvement in the free radical oxidation reactions, playing an important role in the pathogenesis of both diseases.

[Semax in the treatment of glaucomatous optic neuropathy in patients with normalized ophthalmic tone]

A complex of neuroprotective therapy, including a new Russian neuropeptide semax, was used in the treatment of glaucoma patients with normalized ophthalmic tone. Electrophysiological and computer methods of examination demonstrated the advantages of new therapy over traditional neuroprotective treatment for glaucoma. The efficiency is due to pathogenetic activity of semax possessing both neuroprotective and neurotrophic effects.

N-Acetylcarnosine, a natural histidine-containing dipeptide, as a potent ophthalmic drug in treatment of human cataracts

A study was designed to document and quantify the changes in lens clarity over 6 and 24 months in 2 groups of 49 volunteers (76 eyes) with an average age of 65.3 +/- 7.0 enrolled at the time of diagnosis of senile cataracts of minimal to advanced opacification. The patients received N-acetylcarnosine, 1% sol (NAC) (26 patients, 41 eyes = Group II), placebo composition (13 patients, 21 eyes) topically (two drops, twice daily) to the conjunctival sac, or were untreated (10 patients, 14 eyes); the placebo and untreated groups were combined into the control (reference) Group I. Patients were evaluated upon entry, at 2-month (Trial 1) and 6-month (Trial 2)-intervals for best corrected visual acuity (b/c VA), by ophthalmoscopy and the original techniques of glare test (for Trial 1), stereocinematographic slit-image and retro-illumination photography with subsequent scanning of the lens. The computerized interactive digital analysis of obtained images displayed the light scattering/absorbing centers of the lens into 2-D and 3-D scales. The intra-reader reproducibility of measuring techniques for cataractous changes was good, with the overall average of correlation coefficients for the image analytical data 0.830 and the glare test readings 0.998. Compared with the baseline examination, over 6 months 41.5% of the eyes treated with NAC presented a significant improvement of the gross transmissivity degree of lenses computed from the images, 90.0% of the eyes showed a gradual improvement in b/c VA to 7-100% and 88.9% of the eyes ranged a 27-100% improvement in glare sensitivity. Topographic studies demonstrated less density and corresponding areas of opacification in posterior subcapsular and cortical morphological regions of the lens consistent with VA up to 0.3. The total study period over 24 months revealed that the beneficial effect of NAC is sustainable. No cases resulted in a worsening of VA and image analytical readings of lenses in the NAC-treated group of patients. In most of the patients drug tolerance was good. Group I of patients demonstrated the variability in the densitometric readings of the lens cloudings, negative advance in glare sensitivity over 6 months and gradual deterioration of VA and gross transmissivity of lenses over 24 months compared with the baseline and 6-month follow-up examinations. Statistical analysis revealed the significant differences over 6 and 24 months in cumulative positive changes of overall characteristics of cataracts in the NAC-treated Group II from the control Group I. The N-acetylated form of natural dipeptide L-carnosine appears to be suitable and physiologically acceptable for nonsurgical treatment for senile cataracts.

[Method for assessing involution ophthalmoendotoxicosis by fluorescent analysis of lacrimal fluid]

A method for evaluating the binding capacity of aqueous humor albumin as endoophthalmotoxicosis indicator is proposed, consisting in evaluation of this parameter in the lacrimal fluid by fluorescent probe K-35. A correlation between the studied parameter in aqueous humor, lacrimal fluid, and blood serum has been detected. Albumin binding capacity in the above biological fluids of patients with involution ophthalmopathy was low.

[The pathomorphological characteristics of the cataractous lens in glaucoma patients]

Lenses from patients with glaucoma and senile cataract (control) were examined under electron microscope. Ultrastructural changes in the lenses of glaucoma patients differ from changes in senile cataract by a more pronounced thinning of the capsule and development of microdefects in it and in many cases by accumulation of amorphous material on the surface of the posterior capsule adjacent to the vitreous body. This material may be pseudo-exfoliate or a manifestation of stratification of the posterior capsule proper. Development of a pseudomembrane on the surface of posterior capsule is a manifestation of proliferative processes in glaucoma. These features in a certain measure reflect the mechanism of cataract development in glaucoma, which helps plan the measures for preventing it. The status of posterior lenticular capsule in glaucoma is to be taken into consideration when implanting intraocular lenses.

[Crystallography of the lacrimal fluid as a method for predicting the risk of developing cataract in patients with primary glaucoma]

Results of crystallographic analysis of the lacrimal fluid in patients with glaucoma combined with cataract are analyzed. The characteristic features of lacrimal crystallograms of such patients consist in changed ratio of the crystallization zones with disappearance of the intermediate zone and appearance of stellate structures on crystallograms of patients with progressing cataracts. The method of lacrimal crystallography is suggested to be used in examinations of patients with glaucoma.

[Permeability of blood-eye barrier in patients with primary glaucoma combined with lens opacity]

The development of glaucoma involves changes in the chamber humor caused by hydrodynamic disorders. Primary glaucoma is often combined with lens opacities. Comparison of the content of protein and protein fractions in aqueous humor and blood serum of patients with glaucoma and different degree of lens opacity showed that, in contrast to senile cataract, cataract in a glaucomatous eye forms when the permeability of the blood-eye barrier is increased, which justifies the administration of drugs stabilizing it.

[Comparative study of antiradical effects of several antiglaucoma drugs]

Studies of the in vitro inhibitory effects of drugs most often used in the treatment of primary glaucoma on the generation of the main active oxygen forms (hydroxyl radical, superoxide anion radical, singlet oxygen and radical products of hydrogen peroxide and peroxidase reaction) showed that antiradical activity is more intrinsic for thimolol and decreases in the following series: betoptic-pilocarpinclofelin. This once more validates the efficacy of beta-blockers in the treatment of glaucoma and prevention of cataract associated with it.

[Ultrasonography of lens crystalline in patients with primary open-angle glaucoma]

One- and two-dimensional examination of the lens supplemented with biometry was carried out in patients with primary open-angle glaucoma. Echobiometry revealed a relationship between the thickness of the lens and type of cataract. Analysis of echographic images of the lens and biomicroscopy findings demonstrated the value of this method for the early objective assessment of cataract progress in patients with glaucoma, specifically, after antiglaucoma surgery.

[Role of free radical oxidation reaction in lens opacities after antiglaucoma surgery]

The content of lipid peroxidation products (malonic dialdehyde) in the aqueous humor is increased in patients with mature cataracts developing after antiglaucoma surgery. Antioxidative activity of the humor was decreased. A relationship was revealed between the postoperative changes in ocular hydrodynamics and metabolic disorders in the chamber humor (reduction of the antioxidative activity of the humor and its suppressed production), which explains one mechanism of cataract development in patients operated on for glaucoma.

[Immunological prognostication of the risk of cataract development after glaucoma surgery]

AntiDNA antibodies in the serum and lacrimal fluid are reliably more often detected by enzyme immunoassay in glaucoma patients with signs of lens opacity than in those with transparent lens. The presence of antibodies to denaturated DNA in the serum and/or lacrimal fluid may serve as the prognostic criterion of a high risk of cataract development and progress after antiglaucoma surgery. The informative periods for immunological examinations if the period before the operation and 3 months after it.

[Contribution of free-radical reactions of chamber humor to the development of primary open-angle glaucoma]

The level of lipid peroxidation products (malonic dialdehyde) is more than two times increased in the anterior chamber humor in patients with far advanced glaucoma in comparison with the well-developed stage. The level of the total antioxidant activity of humor is reliably lowered. A correlation has been revealed between the antioxidant activity of humor and its production. These results prompt us to recommend antioxidants for therapy of primary glaucoma.