RETINA VESSELS CHANGES IN CHORNOBYL NUCLEAR POWER PLANT EMPLOYEES WHO EXPERIENCED LONG-TERM ABNORMAL RADIATION EXPOSURE AT THE WORKPLACE AS A RESULT OF THE OCCUPATION OF CHORNOBYL NUCLEAR POWER PLANT IN 2022. / ZMINY SUDYN SITKIVKY V SPIVROBITNYKIV ChORNOBYL'S'KOÏ ATOMNOÏ ELEKTROSTANTsIÏ, IaKI ZAZNALY TRYVALOGO NENORMOVANOGO RADIATsIINOGO VPLYVU NA ROBOChOMU MISTsI VNASLIDOK OKUPATsIÏ ChAES U 2022 ROTsI.

During the occupation of the Chornobyl Nuclear Power Plant (ChNPP) in 2022, a group of employees remained in the working town for a long time. These personnel were exposed to long-term radiation and non-radiation factors of the production environment, as well as stress and other factors. These factors could result in negative changes of health.It is known that radiation exposure causes changes in the course and caliber of retinal vessels. OBJECTIVE: to assess the condition of retinal arteries and veins and the level of incorporated 137Cs content in persons who were exposed to prolonged exposure to radiation and non-radiation factors of industrial environment, as they were at the workplace overtime during the occupation of the Chornobyl Nuclear Power Plant in 2022. MATERIALS AND METHODS: A comprehensive ophthalmological examination was carried out. Which included the determination of the diameter of the retinal arteries and veins, the arteriovenous ratio, of 55 people from among the personnel of the ChNPP, who worked under the conditions of the occupation of the ChNPP. All those examined were examined on an expert human radiation counter. The results of the ophthalmological examination were compared with the results of earlier examinations of ChNPP employees of the same age groups. RESULTS: It was established that in the examined group, a decrease in the arterio-venous ratio was observed, mainly due to the expansion of retinal veins. Dilatation of the veins was asymmetric, mainly the branches of the central vein of the retina of the right eye were more dilated. Retinal arteries were narrowed in all examined subjects. When comparing the results with the data of previous examinations, it was established that the arterio-venous ratio in this group was probably lower than in previously examined employees of the ChNPP of the same age groups. At the same time, the maximum registered value of the content of incorporated 137Сs was 713 Bq/organism, none of the examined exceeded the control level of 1,000 Bq/organism. CONCLUSIONS: Violation of blood circulation in the retina was detected - a probable increase in the arteriovenous ratio due to the expansion of the retinal veins in the personnel of the Chornobyl nuclear power plant who worked under the conditions of the occupation of the ChNPP in 2022. Since the examined subjects did not exceed the control level of incorporated 137Сs content (1,000 Bq/organism), the observed effect may be a consequence of the influence of other, both radiation and non-radiation factors.

Smartphone-enabled retinal arteriovenous imaging and correlation with coronary SYNTAX score.

OBJECTIVE: To assess the feasibility of measurement of retinal arteriovenous (AV) ratio using a smartphone, we performed a comparative evaluation with fundus camera imaging and coronary SYNTAX score. METHOD: Successive coronary artery disease (CAD) patients who underwent coronary angiography were recruited for smartphone retinal imaging. Following pupillary dilatation, fundus camera images and smartphone photography were performed. Video images were captured with a smartphone, edited and analysed. Retinal artery and vein size at 0.5 and 1 disc diameter (DD) were measured using DICOM software by two independent observers. Another observer calculated SYNTAX score. RESULTS: Analysable smartphone images were available in 91 (89.2%) of 102 patients. Tobacco use was found in 26%, hypertension in 54%, diabetes in 55%, and high LDL cholesterol in 50%. Median and 25-75 interquartile range (IQR) AV ratio at 0.5 and 1.0 DD, respectively, with smartphone were 0.48 (0.45-0.52) and 0.47 (0.45-0.52) and fundus camera were 0.48 (0.44-0.53) and 0.48 (0.45-0.53) (Spearman's correlation 0.80 and 0.79, p < 0.001). Coronary single vessel disease was in 21%, double vessel in 16%, triple vessel in 55%, normal angiogram in 8%, and median SYNTAX score was 18.0 (8.0-25.0). There was an inverse correlation of SYNTAX score with smartphone-derived AV ratio at 0.5 and 1.0 DD (rho -0.27,p = 0.007 and -0.26,p = 0.009) as well as with fundus camera (rho -0.37 and -0.38, p < 0.001). Trend-analysis showed an inverse association of smartphone AV ratio with increasing CAD (ptrend <0.001). CONCLUSIONS: Smartphone-based retinal AV imaging is feasible and comparable to fundus-camera imaging. There is a significant inverse correlation with coronary angiographic severity.

A Deep Learning Architecture for Vascular Area Measurement in Fundus Images.

Purpose: To develop a novel evaluation system for retinal vessel alterations caused by hypertension using a deep learning algorithm. Design: Retrospective study. Participants: Fundus photographs (n = 10 571) of health-check participants (n = 5598). Methods: The participants were analyzed using a fully automatic architecture assisted by a deep learning system, and the total area of retinal arterioles and venules was assessed separately. The retinal vessels were extracted automatically from each photograph and categorized as arterioles or venules. Subsequently, the total arteriolar area (AA) and total venular area (VA) were measured. The correlations among AA, VA, age, systolic blood pressure (SBP), and diastolic blood pressure were analyzed. Six ophthalmologists manually evaluated the arteriovenous ratio (AVR) in fundus images (n = 102), and the correlation between the SBP and AVR was evaluated manually. Main Outcome Measures: Total arteriolar area and VA. Results: The deep learning algorithm demonstrated favorable properties of vessel segmentation and arteriovenous classification, comparable with pre-existing techniques. Using the algorithm, a significant positive correlation was found between AA and VA. Both AA and VA demonstrated negative correlations with age and blood pressure. Furthermore, the SBP showed a higher negative correlation with AA measured by the algorithm than with AVR. Conclusions: The current data demonstrated that the retinal vascular area measured with the deep learning system could be a novel index of hypertension-related vascular changes.

Characterization of the retinal vasculature in fundus photos using the PanOptic iExaminer system.

BACKGROUND: The goal was to characterize retinal vasculature by quantitative analysis of arteriole-to-venule (A/V) ratio and vessel density in fundus photos taken with the PanOptic iExaminer System. METHODS: The PanOptic ophthalmoscope equipped with a smartphone was used to acquire fundus photos centered on the optic nerve head. Two fundus photos of a total of 19 eyes from 10 subjects were imaged. Retinal vessels were analyzed to obtain the A/V ratio. In addition, the vessel tree was extracted using deep learning U-NET, and vessel density was processed by the percentage of pixels within vessels over the entire image. RESULTS: All images were successfully processed for the A/V ratio and vessel density. There was no significant difference of averaged A/V ratio between the first (0.77 ± 0.09) and second (0.77 ± 0.10) measurements (P = 0.53). There was no significant difference of averaged vessel density (%) between the first (6.11 ± 1.39) and second (6.12 ± 1.40) measurements (P = 0.85). CONCLUSIONS: Quantitative analysis of the retinal vasculature was feasible in fundus photos taken using the PanOptic ophthalmoscope. The device appears to provide sufficient image quality for analyzing A/V ratio and vessel density with the benefit of portability, easy data transferring, and low cost of the device, which could be used for pre-clinical screening of systemic, cerebral and ocular diseases.

Decision support system for detection of hypertensive retinopathy using arteriovenous ratio.

Hypertensive Retinopathy (HR) caused by hypertension is a retinal disease which may leads to vision loss and blindness. Computer aided diagnostic systems for various diseases are being used in clinics but there is a need to develop an automated system that detects and grades HR disease. In this paper, an automated system is presented that detects and grades HR disease using Arteriovenous Ratio (AVR).The presented system includes three modules i.e. main component extraction, artery/vein (A/V) classification and finally AVR calculation and grading of HR. Proposed system uses vascular map and a set of hybrid features for A/V classification. The evaluation of proposed system is carried out using three datasets. The proposed system shows average accuracies of 95.14% for images of INSPIRE-AVR database, 96.82% for images of VICAVR database and 98.76% for local dataset AVRDB. These results support that the proposed system is trustworthy for clinical use in detection and grading of HR disease. Main contribution of proposed system is that it utilizes complete blood vessel map for A/V classification. These arteries and veins are then used to calculate AVR and grade HR cases based on AVR values. Another contribution of this article is that it presents a new dataset AVRDB for A/V classification and HR detection.

Arteriovenous ratio and papilledema based hybrid decision support system for detection and grading of hypertensive retinopathy.

BACKGROUND AND OBJECTIVES: Hypertensive Retinopathy (HR) is a retinal disease which happened due to consistent high blood pressure (hypertension). In this paper, an automated system is presented that detects the HR at various stages using arteriovenous ratio and papilledema signs through fundus retinal images. METHODS: The proposed system consists of two modules i.e. vascular analysis for calculation of arteriovenous ratio and optic nerve head (ONH) region analysis for papilledema.  First module uses a set of hybrid features in Artery or Vein (A/V) classification using support vector machine (SVM) along with its radial basis function (RBF) kernel for arteriovenous ratio. In second module, proposed system performs analysis of ONH region for possible signs of papilledema. This stage utilizes different features along with SVM and RBF for classification of papilledema. RESULTS: The first module of proposed method shows average accuracies of 95.10%, 95.64% and 98.09%for images of INSPIRE-AVR, VICAVR, and local dataset respectively. The second module of proposed method achieves average accuracies of 95.93% and 97.50% on STARE and local dataset respectively. CONCLUSIONS: The system finally utilizes results from both modules to grade HR with good results. The presented system is a novel step towards automated detection and grading of HR disease and can be used as clinical decision support system.

Inter-method agreement in retinal blood vessels diameter analysis between Dynamic Vessel Analyzer and optical coherence tomography.

PURPOSE: To analyze the inter-methods agreement in arteriovenous ratio (AVR) evaluation between spectral-domain optical coherence tomography (SD-OCT) and Dynamic Vessel Analyzer (DVA). METHODS: Healthy volunteers underwent DVA and SD-OCT examination. AVR was measured by SD-OCT using the four external lines of the optic nerve head-centered 7-line cube and by DVA using an automated AVR estimation. The mean AVR was calculated, twice, separately by two independent readers for each tool. RESULTS: Twenty-two eyes of 11 healthy subjects (five women and six men, mean age 35) were included. AVR analysis by DVA showed high inter-observer agreement between reader 1 and 2, and high intra-observer agreement for both reader 1 and reader 2. With regard to AVR analysis on SD-OCT, we found high inter-observer agreement between reader 1 and 2, and low intra-observer agreement for reader 2 but high intra-observer agreement for reader 1. Overall, the mean AVR measured on SD-OCT turned out to be significantly higher than mean AVR measured through DVA (reader 1, 0.9023 ± 0.06 vs 0.8036 ± 0.08; p < 0.001, and reader 2, 0.9067 ± 0.06 vs 0.8083 ± 0.05; p= 0.003). CONCLUSIONS: No inter-method agreement in AVR could be detected in the present study due to bias in measurements (shift between DVA and SD-OCT). We found significant difference in the two noninvasive methods for AVR measurement, with a tendency for SD-OCT to overestimate retinal vascular caliber in comparison to DVA. This may be useful for achieving greater accuracy in the evaluation of retinal vessel in ocular as well as systemic diseases.

Dynamic functionality and static changes of retinal vessels in diabetic patients treated with intravitreal ranibizumab.

AIMS: To investigate the short-term effects of intravitreal ranibizumab on retinal vessel functionality in patients with diabetic macular edema (DME) by Dynamic Vessel Analyzer (DVA). METHODS: Patients presenting with DME were enrolled in the study. All patients underwent a complete ophthalmic evaluation, including optical coherence tomography and dynamic and static vessel analysis, using the DVA before (baseline), 1 week and 1 month after administration of intravitreal ranibizumab. DME subject were compared with diabetic retinopathy (DR) without DME subjects, and with normal non diabetic subjects (controls) matched for age and sex. RESULTS: A total of 45 eyes of 45 subjects (15 eyes for each group) were included in the analysis. In DME patients, dynamic analysis showed a significant decrease in mean arterial dilation from baseline to 1 week. Mean central retinal artery equivalent (CRAE) of DR patients without DME was significantly different from baseline and week 1 of DME eyes. In healthy control subjects, CRAE was significantly different from CRAE at baseline and 1 week on DME patients, but not significantly different from DR patients without DME. CONCLUSIONS: Using DVA in patients with DME, dynamic analysis showed a significant decrease in mean arterial dilation from baseline to 1 week in DME eyes. A significant reduction in arterial vessels could be demonstrated in DME patients compared to DR patients without DME and controls.

Medición de la microcirculación retiniana luego del tratamiento antihipertensivo / Measuring retinal circulation after antihypertensive treatment

Background and objective: With the development of image processing techniques, it has become possible to measure the changes in retinal vessels of hypertensive patients by means of eye fundus photographs. Patients and method: In this paper we aim to classify retinal vessels automatically into arterioles and venules. In order to do so, we have compared three different strategies based on the colour of the pixels in images through an analysis of 78 hypertensive patients' eye fundus images. The first strategy classifies all the vessels by applying a clustering algorithm. The second divides the retinal image into four quadrants and classifies the vessels that belong to the same quadrant independently from the rest of the vessels. The third strategy classifies the vessels by dividing the retinal image into four quadrants that are rotated inside the mentioned image. Results: The third strategy was the one that obtained the best results, since it minimizes the number of unclassified vessels. In the initially analysed set of 20 images, we correctly classified 86.53% of the vessels, and this percentage remains similar in a set of 58 images examined by three medical experts. This confirms the validity of the method that automatically calculates the arteriovenous ratio (AVR).Conclusion: Our results are an improvement on those previously described in the bibliography, reducing the number of non-classified vessels. Furthermore, the method entails low computational costs.

Fundamento y objetivo: El desarrollo de técnicas de procesado de imágenes ha devuelto interés para poder medir de una forma objetiva los cambios en la estructura microvascular del hipertenso a través de las fotografías digitales del fondo de ojo. Pacientes y método: Para clasificar de forma automática los vasos de la retina en arteriolas y vénulas, con una elevada precisión, hemos comparado tres estrategias diferentes basadas en la información del color de los pixeles de la imagen del fondo de ojo, analizando 78 imágenes de fondo de ojo de hipertensos. La primera estrategia clasificaría todos los vasos aplicando un algoritmo de agrupamiento. La segunda divide la retina en cuatro cuadrantes y clasifica los vasos que pertenecen al mismo cuadrante independientemente del resto de los vasos. La tercera estrategia clasifica los vasos dividiendo la retina en cuadrantes que son rotados. Resultados: La mejor estrategia resultó la tercera porque minimiza el error y el número de vasos no clasificados. La característica vectorial más determinante está basada en la media o la mediana del componente gris del espacio de color RGB. Para las 20 imágenes inicialmente analizadas hemos clasificado correctamente el 86.53% de los vasos, y este porcentaje permanece similar en el grupo de 58 imágenes examinadas por tres expertos, lo que confirma la validez del método, para el cálculo del índice arteriovenoso de forma automática. Conclusión: Nuestros resultados son superiores a los descritos previamente, reduciendo además el número de vasos no clasificados. Por otro lado, el costo computacional del método es bajo

Summarising the retinal vascular calibres in healthy, diabetic and diabetic retinopathy eyes.

Retinal vessel calibre has been found to be an important biomarker of several retinal diseases, including diabetic retinopathy (DR). Quantifying the retinal vessel calibres is an important step for estimating the central retinal artery and vein equivalents. In this study, an alternative method to the already established branching coefficient (BC) is proposed for summarising the vessel calibres in retinal junctions. This new method combines the mean diameter ratio with an alternative to Murray׳s cube law exponent, derived by the fractal dimension,experimentally, and the branch exponent of cerebral vessels, as has been suggested in previous studies with blood flow modelling. For the above calculations, retinal images from healthy, diabetic and DR subjects were used. In addition, the above method was compared with the BC and was also applied to the evaluation of arteriovenous ratio as a biomarker of progression from diabetes to DR in four consecutive years, i.e. three/two/one years before the onset of DR and the first year of DR. Moreover, the retinal arteries and veins around the optic nerve head were also evaluated. The new approach quantifies the vessels more accurately. The decrease in terms of the mean absolute percentage error was between 0.24% and 0.49%, extending at the same time the quantification beyond healthy subjects.

Association between retinal vessel caliber and arterial stiffness in a population comprised of normotensive to early-stage hypertensive individuals.

BACKGROUND: Although impairment of the micro- and macrocirculation is considered inherent to sustained hypertension, there is a substantial lack of studies investigating whether an association exists between micro- and macrovascular damage, especially in early-stage hypertension. METHODS: We studied a meticulously selected population, free of diabetes and cardiovascular disease, of 223 individuals: 137 never-treated, newly diagnosed patients with recent onset of hypertension and 86 normotensive individuals. Nonmydriatic retinal photography was used to assess retinal microvascular diameters, including central retinal arteriolar (CRAE) and venular equivalent and arteriovenous ratio (AVR). Arterial stiffness was evaluated by measurement of pulse wave velocity (PWV) and aortic augmentation index (AIx). RESULTS: Compared with normotensive subjects, hypertensive patients exhibited significantly increased PWV (8.1 vs. 7.1 m/sec; P < 0.001) and AIx (23.86% vs. 18.8%; P = 0.01) and decreased CRAE (86.47 vs. 91.44 µm; P = 0.001) and AVR (0.74 vs. 0.78; P = 0.007). A significant inverse association was demonstrated between PWV and CRAE (r = -0.205; P = 0.002), which remained significant after multivariable analysis. Likewise, CRAE (P = 0.04) and AVR (P = 0.02) were independent predictors of AIx. CONCLUSIONS: This study shows for the first time an association between quantitatively assessed retinal abnormalities and increased arterial stiffness in a sample of early-stage hypertensive and normotensive individuals, suggesting that micro- and macrocirculation impairment in hypertension is a dynamic, mutual, interdependent process present from its very early stages. Given the predictive value of both retinal arteriolar narrowing and arterial stiffness in terms of cardiovascular mortality and morbidity, identification of combined micro- and macrovascular damage might be helpful in cardiovascular risk stratification of hypertensive patients.

Reliable monitoring system for arteriovenous ratio computation.

The degree of narrowing or widening in retinal vessels related to several cardiovascular diseases such as hypertension or diabetes may be measured by the arteriovenous ratio (AVR), that is, the relation between the artery and vein retinal vessel widths. Nevertheless, its lack of reproducibility, due mainly to a laborious manual calculation and the dependence of the vessels selected for its estimation, hinders its use in daily medical practice. This variation makes difficult to monitor the patient's condition over time. This paper describes a reliable AVR monitoring system which computes automatically the AVR from several images of the same patient acquired at different times using the same vessels measured at the same points. The system has been evaluated in a large data set of 158 pairs of images and good correlation results between medical experts and the system have been achieved.