GCC Thickness Research Articles

Using Multi-Layer Perceptron Driven Diagnosis to Compare Biomarkers for Primary Open Angle Glaucoma.

To use neural network machine learning (ML) models to identify the most relevant ocular biomarkers for the diagnosis of primary open-angle glaucoma (POAG). Neural network models, also known as multi-layer perceptrons (MLPs), were trained on a prospectively collected observational dataset comprised of 93 glaucoma patients confirmed by a glaucoma specialist and 113 control subjects. The base model used only intraocular pressure, blood pressure, heart rate, and visual field (VF) parameters to diagnose glaucoma. The following models were given the base parameters in addition to one of the following biomarkers: structural features (optic nerve parameters, retinal nerve fiber layer [RNFL], ganglion cell complex [GCC] and macular thickness), choroidal thickness, and RNFL and GCC thickness only, by optical coherence tomography (OCT); and vascular features by OCT angiography (OCTA). MLPs of three different structures were evaluated with tenfold cross validation. The testing area under the receiver operating characteristic curve (AUC) of the models were compared with independent samples t-tests. The vascular and structural models both had significantly higher accuracies than the base model, with the hemodynamic AUC (0.819) insignificantly outperforming the structural set AUC (0.816). The GCC + RNFL model and the model containing all structural and vascular features were also significantly more accurate than the base model. Neural network models indicate that OCTA optic nerve head vascular biomarkers are equally useful for ML diagnosis of POAG when compared to OCT structural biomarker features alone.

Identification of diabetic retinopathy classification using machine learning algorithms on clinical data and optical coherence tomography angiography.

To apply machine learning (ML) algorithms to perform multiclass diabetic retinopathy (DR) classification using both clinical data and optical coherence tomography angiography (OCTA). In this cross-sectional observational study, clinical data and OCTA parameters from 203 diabetic patients (203 eye) were used to establish the ML models, and those from 169 diabetic patients (169 eye) were used for independent external validation. The random forest, gradient boosting machine (GBM), deep learning and logistic regression algorithms were used to identify the presence of DR, referable DR (RDR) and vision-threatening DR (VTDR). Four different variable patterns based on clinical data and OCTA variables were examined. The algorithms' performance were evaluated using receiver operating characteristic curves and the area under the curve (AUC) was used to assess predictive accuracy. The random forest algorithm on OCTA+clinical data-based variables and OCTA+non-laboratory factor-based variables provided the higher AUC values for DR, RDR and VTDR. The GBM algorithm produced similar results, albeit with slightly lower AUC values. Leading predictors of DR status included vessel density, retinal thickness and GCC thickness, as well as the body mass index, waist-to-hip ratio and glucose-lowering treatment. ML-based multiclass DR classification using OCTA and clinical data can provide reliable assistance for screening, referral, and management DR populations.

The association of islet autoantibodies with the neural retinal thickness and microcirculation in type 1 diabetes mellitus with no clinical evidence of diabetic retinopathy.

To examine the association between islet autoantibodies (IAbs) and the retinal neurovascular changes in type 1 diabetes mellitus (T1DM) with no diabetic retinopathy (NDR). This cross-sectional study measured the neural retinal structure and microvascular density of 118 NDR eyes using spectral-domain optical coherence tomography angiography. Retinal structure parameters included retinal thickness (RT), inner retinal thickness (iRT), retina never fibral layer thickness (RNFL thickness), ganglion cell complex thickness (GCC thickness), and loss volume of GCC. Microvascular parameters included vessel density of superficial capillary plexus (sVD), vessel density of deep capillary plexus, and vessel density of choroid capillary plexus. Comparison and correlation analyses of these OCTA parameters were made with various IAbs, including glutamic acid decarboxylase antibody (GADA), tyrosine phosphatase-related islet antigen 2 antibody (IA2A), and zinc transporter 8 antibody (ZnT8A). A general linear model was used to understand the association of IAbs with the retina parameters. The IAb positive (IAbs +) group, which included 85 patients, had thinner RT (235.20 ± 18.10mm vs. 244.40 ± 19.90mm at fovea, P = 0.021) and thinner iRT (120.10 ± 9.00mm vs. 124.70 ± 6.90mm at parafovea, P = 0.015), compared with the IAb negative (IAbs-) group comprising 33 patients. Furthermore, a more severe reduction of RT was demonstrated in the presence of multiple IAbs. Among the three IAbs, GADA was the most significant independent risk factor of all-round RT decrease (β = -0.20 vs. -0.27 at fovea and parafovea, respectively, P < 0.05), while titers of IA2A negatively affect sVD in the parafovea (β = -0.316, P = 0.003). IAbs are associated with neural retinal thinning and microcirculation reduction in T1DM patients before the clinical onset of diabetic retinopathy.

Effect of mydriasis on macular and peripapillary metrics in swept-source optical coherence tomography angiography.

The study aimed to evaluate the effect of mydriasis on macular and peripapillary metrics with swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects. Thirty-five healthy subjects were included. The macular region was scanned by the 3×3mm mode and 6×6mm mode, and the peripapillary region was scanned by the 4.5×4.5mm mode on both eyes with SS-OCTA before and after mydriasis. Macular and peripapillary metrics, including retinal vessel density (VD) and fundus thickness were measured by the built-in program. Data of the right eye were analyzed. The signal strength of the scans was comparable before and after mydriasis (all P>0.05). There were no significant differences in foveal avascular zone (FAZ) parameters and retinal VD of most sectors in both macular and peripapillary areas (all P>0.05). Choroidal thickness was decreased, outer and whole retinal thickness was increased in most of the macular sectors after mydriasis (all P<0.05). Choroidal thickness was decreased in all the peripapillary sectors, but whole retinal thickness and GCC thickness were increased in some peripapillary sectors after mydriasis (all P<0.05). FAZ parameters and retinal VD in the most macular and peripapillary regions are not affected by mydriasis. The thickness of the choroid is decreased after mydriasis, while the thickness of retinal layers in some sectors may be increased after mydriasis.

Long‐term response to idebenone treatment in a patient with advanced Leber hereditary optic neuropathy

Aims/Purpose: To present a case with advanced LHON and its response to 2‐year‐treatment with idebenone, which was prescribed 13 years after the onset of the disease.Methods: A 40‐year‐old Caucasian male patient with a history of bilateral painless visual loss since the age of 28 was examined at our Ophthalmology department. His brother had also suffered similar visual loss. At presentation ETDRS best corrected visual acuity (BCVA) was counting fingers (CF) in both eyes (BE). Fundoscopy revealed pale optic discs bilaterally. Visual fields (30‐2) showed central scotomas in BE. During OCT/OCTA imaging of the optic disc RNFL and GCC thickness were decreased bilaterally. In electrophysiological assessment with flash visual evoked potentials a reduction in amplitude was recorded in BE but with normal latency. Full‐field ERG was within normal limits in BE. At the genetic test, a mitochondrial point mutation m. 3460 G&gt;A at MT‐ND1 gene was detected, which was compatible with LHON. The patient was prescribed 300 mg idebenone per os three times/day for 24 months. Follow‐up visits were scheduled at 6, 12, 18 and 24 months.Results: At 6‐ and 12‐month follow‐up visits visual acuity, fundoscopic findings and OCT‐RNFL imaging remained unchanged. However, the patient reported subjective visual improvement bilaterally, with greater improvement in the visual field of the left eye. At 18 months following initiation of treatment an improvement of the visual field was documented in BE. No change of the GCC thickness was noted. At 2‐year follow‐up his condition remained improved.Conclusions: Delayed treatment with idebenone in advanced LHON can lead to subjective visual improvement. Moreover, an improvement in visual fields can also be documented even after 18 to 24 months of the initiation of the treatment.

Racial Differences in the Diagnostic Accuracy of OCT Angiography Macular Vessel Density for Glaucoma

To evaluate and compare the diagnostic accuracy of macular vessel density (VD) measured by OCT angiography (OCTA) in individuals of African descent (AD) and European descent (ED) with open-angle glaucoma. Observational, cross sectional study. A total of 176 eyes of 123 patients with glaucoma and 140 eyes of 88 healthy participants from the Diagnostic Innovations in Glaucoma Study. Whole-image ganglion cell complex (wiGCC) thickness and macular VD (parafoveal VD and perifoveal VD) were obtained from 6× 6 macula scans. Area under the receiver operating characteristic (AUROC) curves were used to evaluate the diagnostic accuracy of macular VD and ganglion cell complex (GCC) thickness in AD and ED participants after adjusting for confounders such as age, visual field mean deviation (VF MD), signal strength index, axial length, self-reported hypertension and diabetes. Macular VD and wiGCC measurements. Parafoveal and perifoveal VD were significantly lower in ED than AD patients with glaucoma. Parafoveal and perifoveal VD performed significantly worse in AD participants compared with ED participants for detection of glaucoma (adjusted AUROC, 0.75 [95% confidence interval (CI), 0.62, 0.87], 0.85 [95% CI, 0.79, 0.90], P= 0.035; and 0.82 [95% CI, 0.70, 0.92], 0.91 [95% CI, 0.87, 0.94], respectively; P= 0.020). In contrast to VD, diagnostic accuracy of GCC thickness was similar in AD and ED individuals (adjusted AUROC, 0.89 [95% CI, 0.79, 0.96], 0.92 [95% CI, 0.86, 0.96], respectively; P= 0.313). The diagnostic accuracies of both macular VD and GCC thickness for differentiating between glaucoma and healthy eyes increased with increasing VF MD in both AD and ED participants. Diagnostic performance of OCTA macular VD, but not GCC thickness, for glaucoma detection varies by race. Moreover, macular VD parameters had lower accuracy for detecting glaucoma in AD individuals than in ED individuals. The diagnostic performance of macular VD is race-dependent, and, therefore, race should be taken into consideration when interpreting macular OCTA results. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Screening of Oral Tamoxifen Ocular Toxicity in Breast Cancer Patients

Background Breast cancer is one of the leading cancer types among females worldwide. Prevalence of breast cancer is reported to be the second most common among women. Several treatment lines were prescribed in treatment of breast cancer besides surgical, radiological interventions. Tamoxifen is one of the medical treatments used in postsurgical prophylaxis of breast cancer. Various visual problems were reported with tamoxifen therapy. These include posterior subcapsular cataracts, color vision changes, optic neuritis, and intra-retinal crystals. Aim of the Work The aim of the work was to screen for ocular toxicity of tamoxifen used for treatment of breast cancer patients having no ophthalmic complains and treated with tamoxifen for at least 2 years with dose (20mg per day). Patients and Methods We included 50 female patients with breast cancer treated with Tamoxifen therapy for at least 2 years then we divided them into two groups regarding duration of tamoxifen intake from (2-4) years group and from (5-8) years group, all subjects underwent complete careful history taking and full ophthalmological examination, BCVA was measured using Snellen chart with conversion to log. MAR notation for statistical analysis. Results There was significant correlation between duration of tamoxifen intake and RPE mottling, no other significant correlations were detected, there was no significant difference in mean of BCVA, IOP, cup values, disc parameters, GCC thickness, RNFL zones between the two groups except for (inferior quadrant), macular thickness except in (superior quadrant), OCT layers thinning shows RNFL affection in (34%) of cases, GCC affection in (48%) of cases and macula affection in (64%) of cases, color vision defects was found in (12%) and electrophysiological test changes found in few cases. Conclusion Tamoxifen therapy causes minimal affection on the ocular structure and function, OCT layers thinning (34-64% of cases) preceed the clinical changes this highlights the importance of OCT examination in those patients to evaluate tamoxifen toxicity and further studies will be needed to evaluate reversibility of these changes after stoppage of therapy, main ocular complications associated with tamoxifen therapy were correlated to duration of treatment.

Modeling MOG Antibody-Associated Disorder and Neuromyelitis Optica Spectrum Disorder in Animal Models: Visual System Manifestations.

Mechanisms of visual impairment in aquaporin 4 antibody (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-associated disorder (MOGAD) are incompletely understood. The respective impact of optic nerve demyelination and primary and secondary retinal neurodegeneration are yet to be investigated in animal models. Active MOG35-55 experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6Jrj mice, and monoclonal MOG-IgG (8-18C5, murine), recombinant AQP4-IgG (rAb-53, human), or isotype-matched control IgG (Iso-IgG, human) was administered 10 days postimmunization. Mobility impairment was scored daily. Visual acuity by optomotor reflex and ganglion cell complex thickness (GCC, 3 innermost retinal layers) by optical coherence tomography (OCT) were longitudinally assessed. Histopathology of optic nerve and retina was investigated during presymptomatic, acute, and chronic disease phases for immune cells, demyelination, complement deposition, natural killer (NK) cell, AQP4, and astrocyte involvement, retinal ganglion cells (RGCs), and Müller cell activation. Groups were compared by nonparametric tests with a p value <0.05 indicating statistical significance. Visual acuity decreased from baseline to chronic phase in MOG-IgG (mean ± standard error of the mean: 0.54 ± 0.01 to 0.46 ± 0.02 cycles/degree, p < 0.05) and AQP4-IgG EAE (0.54 ± 0.01 to 0.43 ± 0.02, cycles/degree, p < 0.05). Immune cell infiltration of optic nerves started in presymptomatic AQP4-IgG, but not in MOG-IgG EAE (5.85 ± 2.26 vs 0.13 ± 0.10 macrophages/region of interest [ROI] and 1.88 ± 0.63 vs 0.15 ± 0.06 T cells/ROI, both p < 0.05). Few NK cells, no complement deposition, and stable glial fibrillary acid protein and AQP4 fluorescence intensity characterized all EAE optic nerves. Lower GCC thickness (Spearman correlation coefficient r = -0.44, p < 0.05) and RGC counts (r = -0.47, p < 0.05) correlated with higher mobility impairment. RGCs decreased from presymptomatic to chronic disease phase in MOG-IgG (1,705 ± 51 vs 1,412 ± 45, p < 0.05) and AQP4-IgG EAE (1,758 ± 14 vs 1,526 ± 48, p < 0.01). Müller cell activation was not observed in either model. In a multimodal longitudinal characterization of visual outcome in animal models of MOGAD and NMOSD, differential retinal injury and optic nerve involvement were not conclusively clarified. Yet optic nerve inflammation was earlier in AQP4-IgG-associated pathophysiology. Retinal atrophy determined by GCC thickness (OCT) and RGC counts correlating with mobility impairment in the chronic phase of MOG-IgG and AQP4-IgG EAE may serve as a generalizable marker of neurodegeneration.

Comparison of the retinal microvasculature between compressive and glaucomatous optic neuropathy.

To compare the patterns of retinal microvasculature change in the peripapillary and macular region between compressive optic neuropathy (CON) and glaucomatous optic neuropathy (GON), and to assess the ability of optical coherence tomography angiography (OCTA) in differentiating the two conditions. This cross-sectional study included 108 participants (108 eyes), 36 with CON, 36 with GON, and 36 healthy controls. The CON and GON eyes were matched by the average peripapillary retinal nerve fiber layer (pRNFL) thickness (1:1). Optical coherence tomography (OCT) and OCTA were performed to compare the structural and vascular change of the peripapillary and macular region between groups. Both CON and GON eyes showed more severe structural and vascular damage than the control eyes. The CON eyes had lower pRNFL thickness than the GON eyes in the temporal and nasal quadrants, and thicker pRNFL thickness in the inferior quadrant. The average GCC thickness did not differ between the two groups. The peripapillary vessel density of the CON group was significantly higher in the inferior sectors than that of the GON group. In the macular region, the CON group had significantly higher vessel density in the whole image, the temporal sector in parafovea region, and the temporal, superior, and inferior sectors in perifovea region. To a similar degree of structural damage, CON had less retinal vascular impairment than GON, especially in the macular region, and the significance of the finding needs further evaluation.

Value of optical coherence tomography measurement of macular thickness and optic disc parameters for glaucoma screening in patients with high myopia

The basic method of glaucoma diagnosis is visual field examination, however, in patients with high myopia, the diagnosis of glaucoma is difficult. To explore the value of optical coherence tomography (OCT) for measuring optic disc parameters and macular thickness as a screening tool for glaucoma in patients with high myopia. Visual values (contrast sensitivity, color vision, and best-corrected visual acuity) in three groups, patients with high myopia in Group A, patients with high myopia and glaucoma in Group B, and patients with high myopia suspicious for glaucoma in Group C, were compared. Optic disc parameters, retinal nerve fiber layer (RNFL) thickness, and ganglion cell layer (GCC) thickness were measured using OCT technology and used to compare the peri-optic disc vascular density of the patients and generate receiver operator characteristic (ROC) test performance curves of the RNFL and GCC for high myopia and glaucoma. Of a total of 98 patients admitted to our hospital from May 2018 to March 2022, totaling 196 eyes in the study, 30 patients with 60 eyes were included in Group A, 33 patients with 66 eyes were included in Group B, and 35 patients with 70 eyes were included in Group C. Data were processed for Groups A and B to analyze the efficacy of RNFL and GCC measures in distinguishing high myopia from high myopia with glaucoma. The area under the ROC curve was greater than 0.7, indicating an acceptable diagnostic value. The value of OCT measurement of RNFL and GCC thickness in diagnosing glaucoma in patients with high myopia and suspected glaucoma is worthy of development for clinical use.

Impact of adherence to gluten-free diet in paediatric celiac patients on optical coherence tomography findings: Ocular imaging based study

ObjectiveThis study aims to measure choroidal thickness, retinal nerve fiber layer thickness, GCC thickness, and foveal thickness by optical coherence tomography and to investigate whether there is a difference between celiac patients who adhere to the gluten-free diet and who do not. Materials and methodsA total of 68 eyes of 34 pediatric patients diagnosed with celiac disease were included in the study. Celiac patients were divided into two groups those who adhere to the gluten-free diet and those who do not. Fourteen patients who adhere to the gluten-free diet and 20 patients who do not adhere to the gluten-free diet were included in the study. Choroidal thickness, GCC, RNFL, and foveal thickness of all subjects were measured and recorded using an optical coherence tomography device. ResultsThe mean choroidal thickness of the dieting and non-diet groups was 249.05 ± 25.60 and 244.18 ± 33.50 µm, respectively. The mean GCC thickness of the dieting and non-diet groups was 96.56 ± 6.26 and 93.83 ± 5.62 µm, respectively. The mean RNFL thickness of the dieting and non-diet groups was 108.83 ± 9.97 and 103.20 ± 9.74 µm, respectively. The mean foveal thickness of the dieting and non-diet groups was 259.25 ± 33.60 and 261.92 ± 32.94 µm, respectively. There was not a statistically significant difference between the dieting group and the non-diet group in terms of choroidal, GCC, RNFL and foveal thicknesses (p = 0.635, p = 0.207, p = 0.117, p = 0.820, respectively). ConclusionIn conclusion, the present study states that adhering to a gluten-free diet does not make any difference in choroidal, GCC, RNFL, and foveal thicknesses in pediatric celiac patients.

Optical coherence angiography of optic disc in eyes with primary open‐angle glaucoma and normal tension glaucoma with equal levels of structural damage

AbstractPurpose: To compare visual field (VF), nerve fibre and ganglion cell loss and changes in peripapillary vasculature in age matched patients with normal‐tension (NTG) and high tension glaucoma (HTG) at an equal level of glaucomatous structural damage of the optic nerve head (ONH).Methods: For the present study a retrospective analysis of patients with NTG and HTG was performed. One eye of each patient was randomly assigned for further analysis. To provide a reliable case by case match of HTG and NTG eyes, an equal optic disk size as measured by available spectral‐domain OCT system (RTVue XR OCT Avanti System; Optovue Inc., Fremont, CA) and an equal estimated excavation of the optic disk were chosen. Optic nerve head parameters, retinal nerve fibre layer (RNFL) ganglion cell (GCC) thickness and vessel densities (VD) in the peripapillary area were measured automatically by OCT with a respective software. Forty eyes with NTG, were matched according to the same glaucomatous ONH damage based on cup to disc ratio rim area and disc size with 40 eyes with HTG.Results: Mean age of patients was 68.5 ± 12 (27–84) years. The visual field index, RNFL, GCC thickness and peripapillary VDs in the HTG eyes were similar to those in the NTG eyes (mean VFI 79.6 vs. 78.8 p = 0.84, mean RNFL thickness 71.5 vs. 72.05 μm p = 0.87, mean GCC thickness 76.2 vs. 74.5 μm p = 0.62, mean peripapillary VD 43.6 vs. 43.8% p = 0.87). There was no difference in sectoral RNFL thickness and peripapillary VDs between HTG and NTG. In both groups, univariate regression analysis using the Pearson correlation coefficient showed VFI significantly correlated with RNFL thickness (NTG r = 0.423 p = 0.006 HTG r = 0.514 p = 0.002), and peripapillary VD (NTG r = 0.793 p &lt; 0.001 HTG p = 0.534 p = 0.001) in both groups but with GCC thickness (NTG r = 0.585 p &lt; 0.001) only in eyes with NTG.Conclusions: At an equal level of glaucomatous structural damage of the ONH indicated by cup to disk ratio and RNFL thickness, NTG patients seem to have same losses of peripapillary vasculature. Visual field index correlated with RNFL thickness and peripapillary vessel density in both groups.

Correlation between OCT-angiography and photopic negative response in patients with primary open angle glaucoma

PurposeTo evaluate the association between OCT-angiography (OCTA) and photopic negative response (PhNR) in open angle glaucoma (OAG) patients and assess the diagnostic accuracy of these parameters in early detection of glaucoma.MethodsA total of 152 eyes were enrolled in this study, 28 eyes with mild POAG (group I), 44 eyes with moderate-severe POAG (group 2) & 80 eyes of healthy subjects (control group). Full ophthalmological examination, OCTA and PhNR measurements were underwent for all participants. RNFL, GCC thicknesses, PhNR (implicit time and amplitude) were recorded. The superficial and deep capillary plexus vessel density (SCP-VD%, DCP-VD%) were measured by using 6 × 6 mm macula OCTA scans. The peripapillary vessel density (RPC-VD %) were measured by using 4.5 × 4.5 mm optic disk head OCTA scans.ResultsThere were reduction of the median Interquartile range (IQR) thickness of the GCC and RNFL in OAG eyes versus normal (P < 0.001). RPC-VD%, SCP-VD % and DCP-VD% were significantly reduced in OAG eyes versus normal (P < 0.001). Increased OAG severity was associated with more reduction in PhNR amplitude and increased implicit time. Reduced PhNR amplitude and prolonged latency were significantly correlated with reduced vascular parameters. The RCP-VD and PhNR amplitude demonstrated higher diagnostic accuracy (98.7) with the largest AUC and higher sensitivity and specificity (100% & 98.7%, respectively), followed by the PhNR implicit time with (AUC = 0.995) with a diagnostic accuracy 98.7. The SCP-VD, RNFL and GCC thickness had a diagnostic accuracy of (75.0, 81.6 & 84.2), respectively (P < 0.001).ConclusionsOCTA vascular parameters displayed significant positive correlation with PhNR amplitude and significant negative correlation with PhNR implicit time. OCTA and PhNR parameters showed a high diagnostic accuracy for detection of glaucoma, and both may provide promising insight in early detection of glaucoma.This study was retrospectively registered on ClinicalTrials.gov (identifier, NCT05104294).

Retinal nerve fiber and ganglion cell complex layer thicknesses mirror brain atrophy in patients with relapsing-remitting multiple sclerosis.

Multiple sclerosis (MS) is associated with progressive brain atrophy, which in turn correlates with disability, depression, and cognitive impairment. Relapsing-remitting multiple sclerosis (RRMS) is a type of MS in which relapses of the disease are followed by remission periods. This is the most common type of the disease. There is a significant need for easy and low-cost methods to these cerebral changes. Changes in retinal layer thickness may reflect alterations in brain white and gray matter volumes. Therefore, this paper aims to determine whether retinal layer thickness, measured using optical coherence tomography (OCT), correlates with volumetric brain assessments obtained by magnetic resonance imaging (MRI). This retrospective cohort study recruited 53 patients with relapsing-remitting MS who underwent MRI and OCT examinations for evaluation of brain compartment volumes and thickness of retinal layers, respectively. OCT parameters, including central retinal thickness; retinal nerve fiber layer thickness (RNFL, peripapillary thickness); ganglion cell complex thickness (GCC, macular thickness); and Expanded Disability Status Scale (EDSS) results were compared with MRI parameters (cerebral cortex; cerebral cortex and basal ganglia combined; brain hemispheres without the ventricular system; and white matter plaques). We also checked whether there is a correlation between the number of RRMS and OCT parameters. Our primary objective was to identify whether these patients had retinal thickness changes, and our secondary objective was to check if those changes correlated with the MRI brain anatomical changes. RNFL and GCC thicknesses were strongly (p-value < 0.05) associated with (i) cerebral cortex volume, (ii) combination of brain cortex and basal ganglia volumes, and (iii) the hemispheres but without the ventricular system. White matter plaques (combined) showed only weak or no correlation with RNFL and GCC. There was no correlation between central retinal thickness and brain compartment volumes, and there were weak or no correlations between the summary EDSS scores and OCT results. Retinal layer thickness measured by OCT correlates with select volumetric brain assessments on MRI. During the course of RRMS, the anatomo-pathological structure of the retina might serve as a surrogate marker of brain atrophy and clinical progression within selected domains.

Retrograde trans-synaptic axonal degeneration in post-geniculate lesions

: The concept of retrograde axonal degeneration is well studied for visual pathway lesions upto lateral geniculate body. Since clinically evident optic nerve head changes and papillary changes are usually absent in post geniculate lesions, very few studies have been reported to look for the presence of retrograde axonal degeneration in these lesions.To analyse RNFL and GCC thickness in patients with retrogeniculate lesions using Spectral Domain OCT and to determine any characteristic thinning pattern corresponding to the visual field defect.: Patients attending Ophthalmology OPD as diagnosed cases of unilateral retrochiasmal lesions were included in the study. Those who showed homonymous hemianopia corresponding to the retrochiasmal lesions were subjected to OCT RNFL and GCC. Spectral domain OCT was performed on all patients using ZEISS Cirrus HD-OCT Model 400.: Mean age of the study population was 55.5±14.02 years. 21(70%) patients were males, 9(30%) were females. Ipsilateral eyes have superior RNFL thinning, contralateral eyes have inferior, nasal and temporal quadrants thinning. Average RNFL thickness and GCC thickness was reduced in the contralateral eyes. In ipsilateral eyes, temporal GCC was thinner compared to nasal, whereas in contralateral eyes, nasal GCC was thinner compared to temporal. : The pattern of RNFL and GCC thinning corresponds with pattern of visual field loss. The thinning of RNFL and GCC is in accordance to the known trajectories of the crossed and uncrossed projections arising in the nasal and temporal hemiretinae respectively. Our study substantiates that retrograde axonal degeneration occurs in post geniculate lesions also.

Retinal vascular impairment matched to the pulmonary damage in early post-COVID 19 patients.

Endothelium damage is a crucial element in the pathogenesis of SARS-Cov-2 infection. Most casualties in critical COVID-19 cases are due to ARDS, diffuse coagulopathy and cytokine storm. ARDS itself is a consequence of pulmonary endothelial cells damage. Damage to retinal capillary microcirculation in post-infective period has been investigated through Optical Coherence Tomography Angiography (OCTA). The aim of the present study is to find a correlation between signs of retinal vascular damage and pulmonary impairment. Patients admitted to hospital and subsequently recovered from COVID-19 infection were summoned 1 month later to undergo coherence tomography (CT) scan and OCTA examination. The study population included 87 COVID-19 patients with a mean age of 54.28 ± 14.44 years. Oxygen therapy, non-invasive and invasive mechanical ventilation were necessary in 33, 11 and 4 patients respectively to provide respiratory support during the acute course of the disease. Pulmonary involvement interested 54 patients (62.1%). Peripheral (27.6%) or diffuse (29.9%) involvement and ground glass (GG) opacities (47.1%) represented the prevalent radiological finding. A reduced RCPI FI was independently correlated with the presence of reticulation pattern in CT scan (p = .019). Also, RNFL and GCC were thinner in patients who displayed reticulation pattern (respectively p = .025 and p = .015). A reduction in RPCP-FI and RNFL and GCC thickness were independently correlated to the presence of CT reticulation pattern. This association can reflect cytokine induced remodeling in both organs as a consequence of systemic endothelial damage and inflammation.

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

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). 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. 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). 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.

Study of Retinal and Choroidal Changes in Children with Sickle Cell Disease using Optical Coherence Tomography and Angiography

Abstract Background Sickle cell disease is known to cause vaso-occlusive peripheral retinopathy as a result of the microvascular insults that occur when sickled erythrocytes affect the retinal and choroidal blood flow. This leads to non-proliferative retinopathy (NPR) and proliferative retinopathy (PR) that can result in vision affection. While sickle cell retinopathy (SCR) in adult patients is well described, less is known about the retinal changes that occur in pediatric patients. To date, most studies have been of adults. Objective To screen children with sickle cell disease for the presence of retinal and choroidal changes and to compare the findings with age and sex matched controls by performing structural SD-OCT and OCTA and to correlate between findings. This aimed to assess the prevalence and age of onset of retinopathy among pediatric patients. Patients and Methods This cross sectional study was carried out from February 2020 to August 2020 on 30 eyes of patients attending outpatient clinic of Ophthalmology and Pediatric Departments of Ain Shams University Hospitals. Those patients were asked to participate and were enrolled in this study. The ethical standards stated by the ethical committee of Ain Shams University Hospitals were followed. Informed written consent was taken from guardians of all participants. Results There was a significant difference between the cases and control groups regarding the SCP and DCP vessel density, FAZ area, vascular disc density, central macular thickness, choroidal thickness, RNFL average thickness, IS/OS and C/D vertical ratio. However, there was no significant difference between the cases two groups regarding the GCC. There was a significant positive correlation between the retinal thickness and the vessel density in the SCP and DCP in the corresponding subfields. There was a positive statistically significant correlation between the Hb F level and the vessel density of the SCP and DCP. Also, there was a negative statistically significant correlation between the Hb F level and the FAZ. There was a negative statistically significant correlation between the Hb S level and the choroidal thickness, GCC and RNFL average thickness. There was also a statistically significant negative correlation between the disease duration and the temporal parafoveal retinal thickness. Conclusion SD-OCT and OCTA were able to detect areas of thinning and decreased vascular densities in asymptomatic sickle cell children. This study demonstrated a decreased vessel density on OCTA but a normal retinal thickness on SD-OCT in some of the parafoveal sucfields. This suggests that OCTA can detect microvascular abnormalities and retinopathy early even before it is visible on OCT. Further longitudinal studies are needed to examine the vascular densities and retinal and choroidal thinning in sickle cell disease children and their correlation with the various disease parameters.

Optical coherence tomography angiography vessel density parameters in primary open-angle glaucoma

BackgroundMany studies suggest the existence of an alteration of the retinal hemoperfusion in primary open-angle glaucoma. The OCT-A is a novel technique that allows to provide information on retinal microcirculation in a non-invasive way, thus it represents a possible imaging target for the early diagnosis and follow-up of glaucoma. The aim of our work is to evaluate the contribution of vascular parameters provided by OCT-A and their diagnostic abilities in the different stages of primary open-angle glaucoma. MethodThis is a prospective cross-sectional study involving 200 eyes of control subjects and 250 eyes of glaucomatous subjects divided into early glaucoma, moderate glaucoma and advanced glaucoma subgroups. They were assessed for MD, LV by visual field, RNFL and GCC thickness by SS-OCT papillary and macular vascular densities by SS-OCT A. ResultsOCT-A vessel densities determined in the optic nerve head, in the peripapillary and in the macular regions were significantly lower in glaucomatous eyes. Among the vascular parameters studied the whole image vascular density showed the best diagnostic ability in the discrimination between glaucomatous eyes and healthy eyes with an AUC of 0.949. Nevertheless, the diagnostic ability of vascular parameters remains lower than of the structural parameters RNFL (AUC: 0.981). A significant correlation was found between structural, functional and vascular parameters with r < 0.05. The quadratic non-linear model defines better the relationship between structural, vascular and functional damage in glaucoma. ConclusionThe OCT-A plays an important role in the early diagnosis and follow-up of PAOG. It also contributes to the understanding of some aspects of the vascular role in glaucoma.

Оценка фотопического негативного ответа у пациентов с наследственной оптической нейропатией Лебера

Purpose. To assess the retinal ganglion cells function in patients with Leber's hereditary optic neuropathy (LHON) by registering the photopic negative response (PhNR) while the photopic electroretinography is performed. Material and methods. 14 patients with different LHON mutations and 9 healthy individuals were examined. A standard ophtalmological examination was performed, including visual fields, spectral optical coherence tomography, photopic electroretinography and PhNR tests. Results. Significant differences in the PhNR latency (68.4±4.01/64.28±5.37, p&lt;0,01) and the PhNR amplitude (21.5±9.34/32.72±12.73, p&lt;0,003) were revealed in patients with LHON and the control group. The study revealed significant differences between the PhNR latency (р&lt;0.01) and the PhNR amplitude (р&lt;0.008) in patients with visual acuity (VA) ≤ 0.1 and the control group, and between the PhNR amplitude in patients with VA≥0.13 and the control group (р&lt;0.05). There were found significant correlations between the PhNR parameters and visual acuity, mean sensitivity, RNFL and GCC thickness. A strong positive correlation was found between the PhNR amplitude and the GCC thickness in patients with VA≥0.3. Conclusion. The PhNR parameters reflect the retinal ganglion cells function in patients with LHON and correlate with RNFL and GCC structural changes. Key words: Leber hereditary optic neuropathy, mitochondrial optical neuropathies, retinal ganglion cell, photopic negative response, PhNR.