Spectral Optical Coherence Tomography Research Articles

Evaluation of choroidal thickness and retinal nerve fiber layer thickness in Chinese pregnant women and healthy non-pregnant women

PurposeTo evaluate choroidal thickness and retinal nerve fiber layer (RNFL) thickness in different trimesters using enhanced depth imaging optical coherence tomography (EDI-OCT). MethodsA prospective comparative study included 45 healthy pregnant women in the first trimester, 45 women in the second, 45 women in the third and 45 healthy non-pregnant women as the control group. Macular choroidal thickness was measured at three locations: The subfoveal, 1 ​mm temporal, and 1 ​mm nasal from the fovea with EDI-OCT. Peripapillary choroidal thickness (PPCT) and RNFL thickness parameters were automatically calculated by the Spectralis OCT. ResultsThe subfoveal, temporal and nasal macular choroidal thickness were all significantly thicker in the second trimester, compared with those parameters in the first, the third trimesters and the control group (all P ​< ​0.05). The PPCT was significantly increased in the second trimeter compared with the control group at global, temporal, temporal inferior, nasal and nasal inferior positions (all P ​< ​0.05). The RNFL thickness was also significantly increased in pregnant women at nasal superior and nasal inferior quadrants (all P ​< ​0.05). ConclusionsThe choroidal thickness in pregnant women was found to be thicker than the control group, regardless of macular or optic disc location. Findings of RNFL thickening might indicate subclinical involvement of the central nervous system.

Reduction in Retinal Ganglion Cell Layer, Inner Plexiform Layer, and Choroidal Thickness in Children With Autism Spectrum Disorder.

The aim of this study was to evaluate the retinal nerve fiber layer (RNFL), choroidal layer, inner plexiform layer (IPL), and ganglion cell layer (GCL) in patients with autism spectrum disorder (ASD). In this study, we measured the thickness of the RNFL, GCL, IPL, and choroidal thickness using a spectral optical coherence tomography (OCT) device and we compared the results between the children diagnosed with ASD and healthy controls. Correlation between the Childhood Autism Rating Scale (CARS) and the OCT data was evaluated. Both ASD and control group consisted of 40 subjects (30 males and 10 females). Of the children in the ASD group, 29 had normal intelligence and 11 had mild intellectual disability (MID). The mean age of patients in the ASD group and control groups were 9.77 ± 3.37 years and 9.85 ± 3.97 years (p = 0.928). There was a statistically significant difference between the ASD group and the control group in the nasal and nasal-superior sectors of the RNFL layers in the left eye when all the lower layers of RNFL were assessed. In both eyes, the children with ASD had considerably lower mean choroidal thicknesses than the controls. When compared to the controls, the GCL and IPL volumes in the individuals with ASD were considerably lower in both eyes. Compared to the MID group, the left GCL volume of the nasal-inferior group was noticeably higher. A significant correlation was found between CARS scores and left GCL left IPL. In contrast to RNFL in the ASD group, significant reductions in IPL, GCL, and choroidal thickness were observed in both eyes. It is thought that GCL may be a much more important biomarker than RNFL in terms of representing the structural deterioration in the brain. In addition, these results may form the basis for a new perspective on the use of OCT for the diagnosis and clinical course of autism.

Microvascular changes after pars plana vitrectomy for rhegmatogenous retinal detachment repair: A comparative study based on gas tamponade agent.

The purpose of this study was to investigate the effect of gas tamponade on microvascular changes in patients with rhegmatogenous retinal detachment (RRD), who underwent pars plana vitrectomy (PPV), using optical coherence tomography angiography (OCTA). Participants in this study were 48 patients with RRD, who were treated with PPV and gas tamponade without internal limiting membrane peeling. All participants underwent slit-lamp examination, fundoscopy, spectral domain-optical coherence tomography and optical coherence tomography angiography at month 6 postoperatively. The fellow untreated eyes were also examined and served as the control data. A statistically significant enlargement in the foveal avascular zone (FAZ) in both the superficial (p = 0.002) and the deep capillary plexus (p = 0.01) was noticed 6 months postoperatively in patients with RRD treated with PPV compared to the fellow eyes. The foveal avascular zone perimeter was increased in the operated eyes in the deep capillary plexus (p = 0.0003) and the foveal avascular zone circularity was decreased in both the superficial (p = 0.045) and the deep capillary plexus (p < 0.001) compared to the fellow eyes. The vessel density was not significantly different between the operated and the fellow eyes in the superficial and the deep capillary plexus. The vessel density and the foveal avascular zone parameters were comparable between the C3F8 and SF6 groups. Specific microvascular indices as measured by OCTA were statistically different between the operated and the fellow eyes in the superficial and deep capillary plexus. C3F8 and SF6 as gas tamponades did not seem to differ in their impact on the microvascular parameters.

Tau Protein in the Retina

AbstractBackgroundCurrently there is no definite cure for Alzheimer’s therefore early detection is critical. Undetected Alzheimer’s Disease (AD) can lead to severe accidents, neglecting to take essential medications, injury to oneself or others, and/or financial problems. Currently, biomarkers are the most promising way to detect Alzheimer’s early on. Biomarkers such as beta‐amyloid and tau levels taken through invasive mehods or brain scans that involve radiation are among them.As the retina is an extension of the brain and the brain structure, it is possible to detect misfolded proteins via retinal examination non‐invasively. The aim of this study was to discover the binding property of curcumin to both Tau and AB in the retina as a potential biomarker for AD.MethodIn this study, 20 patients were invited with mild AD who had undergone retinal examination within the past 2 years. All the patients had retinal imaging with curcumin which revealed misfolded proteins during the examination and then they were advised to take daily curcumin. The mean age of the patients was 71, and the patients were instructed to take Curcumin Meriva in 500 mg supplements once daily after their prior examinations. All patients had tests repeated with FAF and Heidelberg Spectralis OCT device. The regions with abnormal lesions on FAF were detected and the layer of the defect was scanned by OCT plus compared with the previous imaging of the patients. The images were examined in a masked fashion by 2 specialists.ResultThe images disclosed hyperfluorescent lesions on FAF and OCT revealed accumulations in the inner layers of the retina. Some accumulations had dot shapes and others had fibril‐tangle shapes. Some lesions were present in prior exams, but they were more pronounced and shinier after curcumin use. Their size and shape were in concordance with misfolded proteins in the brain (Figure).ConclusionRetinal examination with curcumin revealed AB plaques in the retina in prior studies. Our study is the first that may demonstrate an easy way to detect the culprit plaque Tau inside the retina of live patients.

Influence of sex on chronic steroid-induced glaucoma: 24-Weeks follow-up study in rats

The objective was to evaluate ocular changes based on sex in steroid-induced glaucoma models in rats comparing healthy controls, over 24 weeks follow-up. Eighty-nine Long–Evans rats (38 males and 51 females) with steroid-induced glaucoma were analysed. Two steroid-induced glaucoma models were generated by injecting poly-co-lactic-glycolic acid microspheres loaded with dexamethasone (MMDEX model) and dexamethasone-fibronectin (MMDEXAFIBRO model) into the ocular anterior chamber. Intraocular pressure was measured by rebound tonometer Tonolab®. Neuroretinal function was analysed using dark- and light-adapted electroretinography (Roland consult® RETIanimal ERG), and structure was analysed using optical coherence tomography (OCT Spectralis, Heidelberg® Engineering) using Retina Posterior Pole, Retinal Nerve Fibre Layer and Ganglion Cell Layer protocols over 24 weeks. Males showed statistically (p < 0.05) higher intraocular pressure measurements. In both sexes and models neuroretinal thickness tended to decrease over time. In the MMDEX model, males showed higher IOP values and greatest percentage thickness loss in the Ganglion Cell Layer (p = 0.015). Females receiving MMDEXAFIBRO experienced large fluctuations in thickness, a higher percentage loss (on average) in Retina Posterior Pole (p = 0.035), Retinal Nerve Fibre Layer and Ganglion Cell Layer than aged-matched males, and the highest thickness loss rate by mmHg. Although no difference was found by sex in dark- and light-adapted electroretinography, increased amplitude in photopic negative response was found in MMDEX males and MMDEXAFIBRO females at 12 weeks. Although both glaucoma models used dexamethasone, different intraocular pressure and neuroretinal changes were observed depending on sex and other influential cofactors (fibronectin). Both sex and the induced glaucoma model influenced neuroretinal degeneration.

Staphyloma-induced Serous Maculopathy: Natural Course and Treatment Effects

To study the natural course of staphyloma-induced serous maculopathy (SISM) and the effects of treatments. Retrospective case series. This retrospective analysis included 26 eyes of 20 patients with SISM and at least 12 months of follow-up. Medical records were reviewed for patient demographics, such as age, sex, spherical equivalent, best-corrected visual acuity (BCVA), type of staphyloma, and imaging characteristics. Spectralis OCT B-scans were evaluated for the presence and height of the serous retinal detachment (SRD) at each follow-up visit. An SRD episode was defined as a period with SRD in 1 patient. Changes in SRD height and BCVA. Twenty-six eyes of 20 patients (70% female) were included. The mean age was 54 ± 11 years, and the mean spherical equivalent was -4.8 ± 3.3 diopters at baseline. The staphyloma was located inferior in 12 eyes (46%), inferonasal in 7 eyes (27%), and nasal in 7 eyes (27%). The mean follow-up duration was 73 ± 34 months. During follow-up, the SRD height fluctuated in all eyes, with a mean change of 125 ± 56 μm. The SRD disappeared completely during follow-up in 13 eyes (50%) and then reappeared in 7 eyes (35%). Resolution occurred spontaneous in 8 eyes (31%). The median time of an SRD episode was 25 (interquartile range 14-57) months. Treatment was performed in 20 eyes (77%) and led to resolution of SRD in 3 of the 15 photodynamic therapy treatments (21%), 2 of 5 (40%) anti-VEGF series, and 2 of 4 eyes (50%) treated with topical prednisolone. Best-corrected visual acuity at the final visit (0.42 ± 0.25) was not significantly different from BCVA at baseline (0.34 ± 0.27 logarithm of the minimum angle of resolution, P= 0.07), nor was BCVA change significantly different between treated eyes (n= 19) and nontreated eyes (n= 7, P= 0.3). Serous retinal detachment in patients with SISM fluctuated over time and resolved without treatment in 31% of the eyes. Because treatment does not change the course of BCVA, a wait-and-see policy is advocated in these patients on the exclusion of treatable causes of SRD. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Crystalline retinopathy in a 6-year-old boy with history of high-dose tamoxifen use.

To report a case of crystalline retinopathy following high-dose tamoxifen use in a pediatric patient. Observational case report. Single patient. A 6-year-old boy with history of over 80 g cumulative tamoxifen use over 25 months for treatment of atypical teratoid/rhabdoid tumor of the posterior fossa presented with a 4-month history of blurred vision. Fundus examination demonstrated multiple superficial foveal refractile opacities in each eye, and spectral optical coherence tomography revealed numerous punctate hyperreflective deposits located within the inner retina. These findings were suggestive of tamoxifen retinopathy. To our knowledge, this is the first report of multimodal retinal imaging of tamoxifen retinopathy in a pediatric patient. Given the risk of permanent vision loss, ophthalmic baseline screening and monitoring should be considered for children receiving tamoxifen.

К вопросу о резистентности диабетического макулярного отека

Purpose. To evaluate the morphofunctional features of diabetic macular edema (DME) and propose a classification of the degree of its resistance. Material and methods. The study included 448 patients (448 eyes) with newly diagnosed DME. A complete ophthalmological examination was performed, including spectral optical coherence tomography of the macular area. All patients were divided into 3 study groups depending on the anti-VEGF drug used: Brolucizumab (138), Ranibizumab (142) and Aflibercept (168). All patients (110) resistant to loading doses of an anti-VEGF drug were switched to intravitreal administration of a dexamethasone-containing implant. The observation period was 6 months. Results. According to the results of our study, the overall percentage of resistance to anti-VEGF therapy in patients with DME was 24.6%. At the same time, in group 1 it was observed in 20.2% of patients, in group 2 in 28.1% and in group 3 in 25.0%. It was found that when switching to intravitreal administration of a dexamethasone-containing biodegradable implant, there was an increase in visual acuity in the studied groups, respectively, from 0.25 to 0.67, from 0.04 to 0.3 and from 0.38 to 0.6 against the background of a decrease in retinal edema. Conclusion. The use of a dexamethasone-containing biodegradable implant after 6 months improved the architectonics of the retinal layers, increased visual acuity and reduced retinal edema in group 1 in 92.9% of patients, in group 2 in 87.5% and in group 3 in 90.5%. The developed clinical classification of the degree of DME resistance, depending on the morphofunctional features of the patient's retina, contributes to making the optimal decision regarding the choice of the most effective initial intravitreal pharmacotherapy for this disease. Key words: diabetic macular edema, anti- VEGF drugs, classification of DME resistance to intravitreal pharmacotherapy, dexamethasone implant

Evaluation of retinal angioarchitectonics by optical coherence angiography and its diagnostic value in functional amblyopia

AIM: This study aimed to evaluate the density parameters of the superficial and deep plexuses of the retina, choriocapillary layer, and avascular zone in eyes with amblyopia of various origins and paired fellow eyes.&#x0D; MATERIAL AND METHODS: The study included 40 patients aged 616 (mean, 8.723.04) years. All patients were divided into 2 groups: group 1 included amblyopic, dysbinocular, and anisometropic eyes (n=48), and group 2 (control group) included paired fellow eyes without amblyopia (n=32). The density of the superficial and deep vascular plexuses of the retina, choriocapillary layer, and avascular zone parameters (area, perimeter, and circumference) were evaluated using spectral optical coherence tomography (RS-3000 Advance 2, Nidek, Japan). Correlation analysis was performed using Pearsons linear correlation coefficient (r).&#x0D; RESULTS: No significant differences were found in the density of the superficial and deep retinal vessels, choriocapillary layer, and avascular zone parameters of the retina in eyes amblyopia of various origins compared with paired fellow eyes (p 0.05). No correlation was found between retinal perfusion data and functional and anatomical parameters of amblyopic eyes.&#x0D; CONCLUSION: No relationship was noted between the vascular parameters of the posterior pole of the eye and the maximally corrected visual acuity, which confirms the absence of changes in retinal perfusion in amblyopia and excludes its role in the pathogenesis.

Normative Percentiles of Retinal Nerve Fiber Layer Thickness and Glaucomatous Visual Field Loss.

Circumpapillary retinal nerve fiber layer thickness (RNFLT) measurement aids in the clinical diagnosis of glaucoma. Spectral domain optical coherence tomography (SD-OCT) machines measure RNFLT and provide normative color-coded plots. In this retrospective study, we investigate whether normative percentiles of RNFLT (pRNFLT) from Spectralis SD-OCT improve prediction of glaucomatous visual field loss over raw RNFLT. A longitudinal database containing OCT scans and visual fields from Massachusetts Eye & Ear glaucoma clinic patients was generated. Reliable OCT-visual field pairs were selected. Spectralis OCT normative distributions were extracted from machine printouts. Supervised machine learning models compared predictive performance between pRNFLT and raw RNFLT inputs. Regional structure-function associations were assessed with univariate regression to predict mean deviation (MD). Multivariable classification predicted MD, pattern standard deviation, MD change per year, and glaucoma hemifield test. There were 3016 OCT-visual field pairs that met the reliability criteria. Spectralis norms were found to be independent of age, sex, and ocular magnification. Regional analysis showed significant decrease in R2 from pRNFLT models compared to raw RNFLT models in inferotemporal sectors, across multiple regressors. In multivariable classification, there were no significant improvements in area under the curve of receiver operating characteristic curve (ROC-AUC) score with pRNFLT models compared to raw RNFLT models. Our results challenge the assumption that normative percentiles from OCT machines improve prediction of glaucomatous visual field loss. Raw RNFLT alone shows strong prediction, with no models presenting improvement by the manufacturer norms. This may result from insufficient patient stratification in tested norms. Understanding correlation of normative databases to visual function may improve clinical interpretation of OCT data.

Choroidal Features of Healthy Iranian Individuals.

To assess subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) profile in the Iranian healthy population and assessment of the inter-eye difference in this regard. In a cross-sectional study, 141 healthy subjects underwent an assessment of refraction and best-corrected visual acuity (BCVA), axial length (AL), and measurement of the intraocular pressure. The imaging of the choroid was performed using the enhanced-depth imaging mode of Spectralis optical coherence tomography from the foveal slab to measure SFCT and calculate CVI. A total of 282 eyes of 141 healthy subjects (59.6% men, mean age of 60.86 ± 11.46 years) enrolled in the current study. The mean SFCT of the right and left eye was 247.40 ± 70.37 and 251.25 ± 72.19, respectively. The mean CVI of the right and left eye was 62.63 ± 3.77 and 63.19 ± 3.91, respectively. None of the measured parameters had statistically significant differences between the left and right eyes. In both univariate and multivariate regression analysis, CVI was significantly associated with BCVA (P < 0.001) but was not associated with age, spherical equivalent (SE), gender, central macular thickness (CMT), and SFCT. In univariate regression analysis, SFCT was significantly associated with age, refraction (P = 0.02), BCVA (P = 0.003), AL (P < 0.001), and CVI (P = 0.02) but not significantly associated with gender and CMT. In multivariate analysis, age (P < 0.001), gender (P = 0.001), and AL (P < 0.001) were significantly associated with SFCT, but SE, BCVA, CVI, and CMT were not significantly associated. This was the first investigation to assess the SFCT and CVI simultaneously in the Iranian population to establish a normative database for future studies. CVI was less variable than SFCT in a healthy population, and no statistically significant differences existed between the left and right eyes.

Современные подходы к оказанию высокотехнологичной офтальмологической помощи детям с ретинопатией недоношенных в Калужском филиале МНТК «Микрохирургия глаза»

Purpose. To present modern approaches to providing high-tech ophthalmic care to children with retinopathy of prematurity (ROP) in Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution. Methods. For the 2003–2022 period screening for detection of active ROP was carried out in 16 000 premature infants. Various stages of the disease were identified in 4129 premature infants (24.9 %). Premature infants with various stages and forms of active ROP have been subjected to multimodal diagnostics of changes in the vascular system of the eye since 2016. Early laser treatment by pattern laser coagulation of the retina using hexagonal patterns was carried out in 226 children (286 eyes) in 2016–2021. Transpupillary laser coagulation of the retina using navigatied laser system was performed in 16 premature babies (26 eyes) in 2021–2023. Primary vitrectomy for severe stage 3 active ROP with the development of extraretinal retinovitreal neovascularization involving the posterior hyaloid membrane was performed in 9 premature infants (12 eyes) in 2021–2023. Results. Based on a comprehensive analysis of the results of multimodal diagnostics, informative prognostic signs of the type of active ROP were established, according to the data of fluorescein angiography of the fundus, spectral optical coherence tomography in the angio mode, and color duplex scanning. These signs provide an accurate definition of the type of course of the disease – a decisive factor in the choice of tactics for managing patients. The developed technologies of pattern hexagonal and navigatied laser coagulation of the retina provide maximal percentage of disease regression. These technologies create the most favorable conditions for further development of visual functions. Primary vitrectomy in all cases made it possible to achieve stable regression of the pathological process. Conclusion. Modern approaches to the provision of high-tech ophthalmic care for children with ROP, implemented in Kaluga branch of S. Fyodorov Eye Microsurgery Federal State Institution, provide high efficiency in the treatment of active ROP with a minimal risk of late complications in the cicatricial period of the disease. Key words: retinopathy of prematurity; multimodal diagnostics; navigated laser coagulation of the retina; primary vitrectomy.

The impact of ocular hypertension on retinal nerve fiber layer and optic disc perfusion during treatment with brolucizumab in patients with neovascular form of age-related macular degeneration

PURPOSE. To evaluate the effect of elevated intraocular pressure (IOP) after multiple intravitreal injections (IVI) of brolucizumab on changes in the retinal nerve fiber layer (RNFL) and perfusion of the optic nerve head.METHODS. The study included 20 patients with newly diagnosed exudative form of age-related macular degeneration (AMD). All patients underwent IVI of brolucizumab. IOP measurements were taken with an ICare Pro tonometer before IVI, one minute after IVI, then after 30 minutes and 180 minutes. Thickness of the peripapillary RNFL was measured using Spectralis OCT (Heidelberg Engineering, Germany). The optic disc was examined using OCT angiography on Revo NX (Optopol Technology SA, Poland). All studies were carried out before the start of treatment, after one month, after the third injection, and one year after the start of treatment.RESULTS. Analysis of peripapillary scans in a patient with a history of multiple IVI a year after the start of treatment with brolucizumab showed a statistically significant decrease in perfusion density and fractal dimensions (skeleton) in the entire optic nerve head (ONH) (p&lt;0.001), in the inner ONH area (p&lt;0.001, p=0.01, respectively), in the nasal sector (p=0.03, p=0.04, respectively), temporal sector (p&lt;0.001) and inferotemporal sector (p=0.03) according to OCT angiography. It was determined that a greater increase of IOP one min after IVI was associated with a greater decrease in the density and fractal dimensions of the radial peripapillary capillaries of the inner ONH (p=0.005, rs=0.5; p=0.004, rs=0.6, respectively). A decrease in RNFL thickness was found one year after the start of IVI treatment with brolucizumab (p&lt;0.001).CONCLUSION. According to OCT angiography, vascular perfusion density of the ONH was decreased during IVI of brolucizumab, and RNFL thickness was also decreased one year after the start of treatment.

Ganglion Cell Layer, Inner Plexiform Layer, and Choroidal Layer Correlate Better with Disorder Severity in ADHD Patients than Retinal Nerve Fiber Layer: An Optical Coherence Tomography Study

Aim: To assess the thickness of the choroidal layer, inner plexiform layer (IPL), ganglion cell layer (GCL), and retinal nerve fiber layer (RNFL) in individuals with attention-deficit/hyperactivity disorder (ADHD).&#x0D; Material and Methods: In this retrospective study, we used a spectral optical coherence tomography (OCT) device. The CPRS-48 was performed to the ADHD group. &#x0D; Results: Both groups consisted of 60 subjects. There were significant differences in NS segment of RNFL (right p=0.039; left p=0.035). The mean right choroidal thickness of ADHD group was significantly lower than the control group (p=0.015). The left GCL and IPL volumes of ADHD group were significantly lower than the control group (p

Identification of Glaucoma in Diabetics Using the Laguna-ONhE Colourimetric Method and OCT Spectralis.

Previous retrospective results are evaluated prospectively and blinded. A total of 221 eyes previously classified as normal (G1), 279 as moderate risk of glaucoma (G2) and 217 as high risk (G3) according to the Globin Discriminant Function (GDF) Laguna-ONhE index were examined with OCT Spectralis- Results: In G1, the Bruch's Membrane Opening Minimum Rim Width (BMO-MRW) was 332 ± 55 microns; in G2, it was 252 ± 47 (p < 0.0001); and in G3, 231 ± 44 (p < 0.0001). In G1, the 1% and 5% percentiles were 233 and 248, respectively; in G2, they were lower in 28.80% and 42.29% of cases, respectively; and in G3, in 50.23% and 63.59% of cases, respectively. Most of the cases were normal-tension glaucomas. Laguna-ONhE indices showed a curvilinear correlation with BMO-MRW results. The Retinal Nerve Fibre Layer (RNFL) showed a poor relationship with BMO. Assuming G1 to be truly normal, BMO-MRW would have a Receiver operating characteristic (ROC) curve area of 0.901 for G2 and G3 and 0.651 for RNFL. A significant reduction in pixels corresponding to vessels was found in G2 and G3 vs. G1 (p < 0.0001). In some cases, these defects appear to be mainly glaucomatous, and in others, they are associated with diabetic microangiopathy. In normal tension glaucoma, RNFL defects may be less severe than those inside the nerve.

Explainable artificial intelligence toward usable and trustworthy computer-aided diagnosis of multiple sclerosis from Optical Coherence Tomography.

Several studies indicate that the anterior visual pathway provides information about the dynamics of axonal degeneration in Multiple Sclerosis (MS). Current research in the field is focused on the quest for the most discriminative features among patients and controls and the development of machine learning models that yield computer-aided solutions widely usable in clinical practice. However, most studies are conducted with small samples and the models are used as black boxes. Clinicians should not trust machine learning decisions unless they come with comprehensive and easily understandable explanations. A total of 216 eyes from 111 healthy controls and 100 eyes from 59 patients with relapsing-remitting MS were enrolled. The feature set was obtained from the thickness of the ganglion cell layer (GCL) and the retinal nerve fiber layer (RNFL). Measurements were acquired by the novel Posterior Pole protocol from Spectralis Optical Coherence Tomography (OCT) device. We compared two black-box methods (gradient boosting and random forests) with a glass-box method (explainable boosting machine). Explainability was studied using SHAP for the black-box methods and the scores of the glass-box method. The best-performing models were obtained for the GCL layer. Explainability pointed out to the temporal location of the GCL layer that is usually broken or thinning in MS and the relationship between low thickness values and high probability of MS, which is coherent with clinical knowledge. The insights on how to use explainability shown in this work represent a first important step toward a trustworthy computer-aided solution for the diagnosis of MS with OCT.

Assessment of resection margins during breast-conserving surgery using multimodal optical coherence tomography

Background. Breast cancer (BC) has been ranked first in morbidity and mortality among the female population in Russian Federation for several years. Rapid and accurate intraoperative examination of the cleanliness of resection margins is the main condition for breast-conserving surgery (BCS) to reduce the risks of local recurrence.Aim. To examine the tumor margins and assess the cleanliness of the resection margins in BCS in patients diagnosed with BC using multimodal optical coherence tomography (MM OCT) with comparative planned histological and additional molecular genetic analysis.Materials and methods. The study was carried out on postoperative samples of tumor and non-tumor breast tissue obtained from 115 patients with BC T1–2N0M0G2–3 stage IA–IIA, after BCS in the volume of radical resection or lumpectomy with histological control of the resection margins. A spectral domain MM OCT device (OCT 1300-E, BioMedTech LLC, Russia) was used, which provides structural OCT images to study the backscattering properties of tissue and allows performing a quantitative assessment of the elastic properties of the tissue by compression optical coherence elastography (OCE).Results. The MM OCT method was able to determine the exact margins between the tumor and non-tumor breast tissue. The main signs of the tumor were a decrease in the level and depth of penetration of the OCT signal in the structural OCT images, as well as an increase in the stiffness values (&gt;200 kPa) in the OCE images with the highest stiffness values (&gt;600 kPa) in the area of tumor cell accumulations. The use of compression OCE made it possible to detect clusters of tumor cells in the margins of resection at a distance of 5 mm from the visible border of the tumor. Among the 132 studied resection margins in 6 cases, the positive resection margin was determined by the OCE method, which was subsequently confirmed histologically. The negative resection margins were characterized by the lowest stiffness values (&lt;200 kPa) in the OCE images and were confirmed by both histological analysis and molecular genetic analysis. ROC-analysis established a threshold stiffness value of 159.8 kPa, which indicates the presence of tumor tissue at the resection margins in the presence of a high stiffness area larger than 500 µm. The high diagnostic accuracy of the OCE method (98.5 %) was determined to distinguish between the negative and positive resection margins during BCS.Conclusion. The use of MM OCT with OCE modality makes it possible to clearly distinguish different types of breast tissue in BC (adipose tissue, connective tissue, accumulation of tumor cells). MM OCT can be used as an additional intraoperative tool for visualizing tumor cells boundaries and assessing the cleanliness of resection margins in real time during BCS.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BIOMARKERS AND MICROPERIMETRY FEATURES IN BEHÇET'S UVEITIS.

To evaluate the parafoveal macular microvasculature and the macular function in patients with retinal vasculitis associated with Behçet's uveitis. In 14 patients with inactive Behçet's uveitis and 26 control individuals (13 with nonocular Behçet's syndrome and 13 healthy subjects), we analyzed the retinal nerve fiber layer, ganglion cell layer, full retinal thickness, foveal avascular zone area and sectorial parafoveal vascular density in the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus using SPECTRALIS optical coherence tomography (OCT) 2 and OCT angiography. Macular sensitivity was analyzed using an MP-3 microperimeter. Eighteen eyes (78%) had a best-corrected visual acuity ≥ 20/25. Significant differences were found in Behçet's uveitis in comparison with the controls on the OCT and OCT angiography: 14.8%, 22.4%, and 14.9% ganglion cell layer thinning in the global, nasal, and inferior sectors, respectively; 6%, 13.2%, and 7.5% full retinal thickness thinning in the superior, nasal, and inferior sectors; and 16.8%, 14.9%, 23.6%, 15.8%, and 12.6% mean deep capillary plexus density reduction in the global, superior, nasal, inferior, and temporal sectors. Microperimetry data demonstrated significant mean reductions of 21% and 23.6% in central and average macular sensitivities and 28.8%, 40.4%, 27.7%, and 24.2% in the superior, nasal, inferior, and temporal sectors, respectively. Outer plexiform layer elevations were observed in Behçet's uveitis (69.6%). Behçet's uveitis presented structural and functional macular damage despite good best-corrected visual acuity, mainly affecting the nasal sector and the deep capillary plexus. On OCT and OCT angiography, quantitative and qualitative changes can be valuable biomarkers of ocular involvement in Behçet's syndrome.

Optical Coherence Tomography: Focus on the Pathology of Macula in Scleritis Patients.

Twenty-four patients diagnosed with scleritis were selected for this study. All of the patients went through basic ophthalmological examinations, such as visual acuity testing (VA), intraocular pressure measurement (IOP), slit lamp examination, ophthalmoscopic examination, and OCT. OCT examinations were taken by SD-OCT Spectralis OCT system (Heidelberg Engineering, Heidelberg, Germany). Twenty-seven eyes of 24 patients (7 males and 17 females) were included in this study, who were diagnosed with scleritis. OCT examinations showed epiretinal membrane (ERM) in three patients (12%), cystoid macular edema (CME) (three cases, 12%), diffuse macular edema (DME) (one case, 4%), and serous retinal detachment (SRD) (one case, 4%). OCT proved to be a valuable, non-invasive method for detecting macular pathology in patients with scleritis. Despite the best treatment regimen applied, macular involvement resulting in reduced visual acuity (VA) can develop, which we could detect with OCT since macular edema (ME) is the leading cause of decreased vision due to the damaged outer blood-retina barrier (BRB) in inflammation. OCT investigation is a highly important method for early detection of ocular complications in scleritis in order to prevent blindness.

The Result of the Treatment of Optic Nerve Edema after COVID-19

The neuro-ophthalmic symptoms and signs associated with COVID-19 infection are varied and span the course of the infection to the convalescent phase. In addition to the anterior segment of the eye, there is a possibility of damage to the posterior segment of the eyeball. The described cases are isolated and there are no results of treatment of patients who have undergone COVID-19.Purpose: To describe the outcome of treatment of bilateral optic nerve edema after COVID-19.Methods. A 59-year-old man with reduced visual functions in the post-surgical period was examined. A standard ophthalmological examination was performed. In addition, spectral optical coherence tomography (OCT) of the macular area of the retina and optic disc (OND) was performed using the RTVue XR Avanti apparatus (Optovue, USA). The patient underwent a laboratory study.Results. Bilateral papilledema was detected in a patient after COVID-19. According to OCT data, a thickening of the nerve fiber layer of the retina of both eyes was revealed, according to OCT angiography, a decrease in the density of the RPC. Conducted a course of conservative and physiotherapy treatment.Conclusion. The COVID-19 epidemic poses several challenges for the ophthalmological community: to determine algorithms for timely diagnosis and treatment, as well as to ensure the prevention of complications from the organ of vision in patients who have undergone COVID-19. It may make sense to screen for coronaviruses in patients with inflammatory diseases of the posterior segment of the eye of unknown etiology. The inclusion of spectral optical coherence tomography with the function of angiography in a comprehensive examination of patients is important for the early detection of microcirculatory and morphometric changes in the optic disc, macular and peripapillary retina. It is advisable to use physiotherapeutic methods of treatment in patients with visual impairment in the post-COVID period, which will reduce the long-term drug load and increase the effectiveness of treatment.