Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 658
Filtrar
1.
Invest Ophthalmol Vis Sci ; 60(14): 4830-4837, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31747685

RESUMO

Purpose: We investigate macular perfusion and the systemic and ocular associations in a population-based setting. Methods: In this cross-sectional study, 2018 adults residing in Hong Kong underwent detailed ophthalmic examinations after consenting to participate. Macular perfusion was measured with optical coherence tomography angiography (OCTA) using the split-spectrum amplitude decorrelation angiography algorithm. The parafoveal flow index and vessel area density were quantified using automated custom-built software. Results: Of the 2018 participants, the OCTA measurements were available for 1940, and 1631 (84.1%) had good quality scans. The right eyes of these 1631 participants (43.1% men) were included for final analysis. Mean age was 49.8 years (range, 18-92 years). Mean global macular vessel density was 47.3% and 55.1% for the superficial and deep retinal layers, respectively. In multivariate analysis, lower superficial vessel density remained significantly associated with lower signal strength index (SSI; P < 0.001, standardized ß = 0.607) and male sex (P < 0.001, ß = 0.162), and borderline associated with older age (P = 0.09, ß = -0.045) and longer axial length (AL; P = 0.09, ß = -0.037), while lower deep layer vessel density was significantly associated with lower SSI (P < 0.001, standardized ß = 0.667), longer AL (P < 0.001, ß = -0.097), and higher creatinine (P < 0.001, ß = -0.072). Conclusions: This large population-based study provided normative OCTA data of macular vessel density and demonstrated that a lower superficial retinal vessel density was significantly associated with lower SSI and male sex, while a lower deep layer retinal vessel density was significantly associated with lower SSI, longer AL, and higher level of creatinine. These associations must be considered when interpreting clinical quantitative OCTA data.


Assuntos
Angiofluoresceinografia , Macula Lutea/irrigação sanguínea , Vasos Retinianos/anatomia & histologia , Tomografia de Coerência Óptica , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Capilares/anatomia & histologia , Capilares/diagnóstico por imagem , Creatinina/sangue , Estudos Transversais , Feminino , Angiofluoresceinografia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia , Retina/fisiologia , Vasos Retinianos/diagnóstico por imagem , Lâmpada de Fenda , Tomografia de Coerência Óptica/métodos , Adulto Jovem
2.
Invest Ophthalmol Vis Sci ; 60(10): 3381-3387, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31387114

RESUMO

Purpose: To investigate the baseline position of the central vascular trunk (CVT) and the characteristics of the optic nerve head (ONH) in newborns. Methods: CVT position was evaluated based on fundus images obtained from newborns who had undergone eye-screening examinations. It was then graded according to the optic disc area as follows: grade 1, within central 4%; grade 2, within central 9%; grade 3, within central 16%; grade 4, within central 25%; grade 5, outside central 25% of optic disc area. The direction of the CVT position was determined in cases of grade 2 or more as superior, inferior, nasal, and temporal, relative to the optic disc center. The ovality index and the vertical cup-to-disc ratio were determined as well. Results: In 1000 fundus images from 1000 newborns, 87.1% showed grade 1 (95% confidence interval 84.7-88.8), and 10.7% showed grade 2. The most common CVT direction was central (87.1%, grade 1), followed by nasal (11.0%) and inferior (1.2%). The ovality index was 1.28 ± 0.09 (range, 1.01-1.61). The ONH shape was vertically oval and highly uniform. The average vertical cup-to-disc ratio was 0.29 ± 0.13 (range, 0.00-0.67). Conclusions: The CVT of newborns was located in the central area of the ONH in most cases. The shape of the optic disc was vertically oval, and very similar among the newborns. Considering the high variability of ONH morphology and the diverse location of the CVT in adults, our result suggests that the shape of the ONH and the CVT position might change during eyeball growth.


Assuntos
Disco Óptico/anatomia & histologia , Disco Óptico/irrigação sanguínea , Vasos Retinianos/anatomia & histologia , Peso ao Nascer , Feminino , Fundo de Olho , Idade Gestacional , Humanos , Recém-Nascido , Masculino
3.
Ann Anat ; 226: 35-47, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31330304

RESUMO

BACKGROUND: Aging of the human retina is accompanied by oxidative stress that exerts profound changes in the retinal neurons. It is unknown if oxidative stress influences the cellular components of the retinal vessels in some ways. METHODS: We examined changes in retinal vessels in human donor eyes (age: 35-94 years; N=18) by light and transmission electron microscopy, TUNEL and immunohistochemistry for biomarkers of vascular smooth muscle cells (SMC; actin), oxidative stress (4-hydroxy 2-nonenal [HNE] and nitrotyrosine), microglia (Iba-1) and vessels (isolectin B4). RESULTS: The earliest changes in the endothelium and pericytes of capillaries are apparent from the seventh decade. With aging, there is clear loss of organelles and cytoplasmic filaments, and a progressive thickening of the endothelial and pericyte basal lamina. Loss of filaments, accumulation of lipofuscin and autophagic vacuoles are significant events in aging pericytes and SMC. Actin immunolabelling reveals discontinuity in arterial SMC layers during eighth decade, indicating partial degeneration of SMC. This is followed by hyalinization, with degeneration of the endothelium and SMC in arteries and arterioles of the nerve fibre layer (NFL) and ganglion cell layer in ninth decade. Iba-1 positive microglia were in close contact with the damaged vessels in inner retina, and their cytoplasm was rich in lysosomes. HNE immunoreactivity, but not of nitrotyrosine, was detected in aged vessels from seventh decade onwards, suggesting that lipid peroxidation is a major problem of aged vessels. However, TUNEL positivity seen during this period was limited to few arteries and venules of NFL. CONCLUSION: This study shows prominent age-related alterations of the pericytes and SMC of retinal vessels. These changes may limit the energy supply to the neurons and be responsible for age-related loss of neurons of the inner retina.


Assuntos
Peroxidação de Lipídeos/fisiologia , Vasos Retinianos/anatomia & histologia , Vasos Retinianos/crescimento & desenvolvimento , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Cadáver , Feminino , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Masculino , Microglia , Microscopia Eletrônica de Transmissão , Pessoa de Meia-Idade , Músculo Liso Vascular/ultraestrutura , Estresse Oxidativo , Fixação de Tecidos
4.
PLoS One ; 14(5): e0215916, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31048908

RESUMO

PURPOSE: Blood vessels of the retina provide an easily-accessible, representative window into the condition of microvasculature. We investigated how retinal vessel structure captured in fundus photographs changes with age, and how this may reflect features related to patient health, including blood pressure. RESULTS: We used two approaches. In the first approach, we segmented the retinal vasculature from fundus photographs and then we correlated 25 parameterized aspects ("traits")-comprising 15 measures of tortuosity, 7 fractal ranges of self-similarity, and 3 measures of junction numbers-with participant age and blood pressure. In the second approach, we examined entire fundus photographs with a set of algorithmic CHARM features. We studied 2,280 Sardinians, ages 20-28, and an U.S. based population from the AREDS study in 1,178 participants, ages 59-84. Three traits (relating to tortuosity, vessel bifurcation number, and vessel endpoint number) showed significant changes with age in both cohorts, and one additional trait (relating to fractal number) showed a correlation in the Sardinian cohort only. When using second approach, we found significant correlations of particular CHARM features with age and blood pressure, which were stronger than those detected when using parameterized traits, reflecting a greater signal from the entire photographs than was captured in the segmented microvasculature. CONCLUSIONS: These findings demonstrate that automated quantitative image analysis of fundus images can reveal general measures of patient health status.


Assuntos
Envelhecimento/fisiologia , Microvasos/anatomia & histologia , Microvasos/fisiologia , Vasos Retinianos/anatomia & histologia , Vasos Retinianos/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea , Estudos de Coortes , Feminino , Fundo de Olho , Humanos , Masculino , Pessoa de Meia-Idade , Fotografação , Adulto Jovem
5.
Int J Med Inform ; 126: 105-113, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31029251

RESUMO

BACKGROUND AND OBJECTIVE: The condition of vessel of the human eye is an important factor for the diagnosis of ophthalmological diseases. Vessel segmentation in fundus images is a challenging task due to complex vessel structure, the presence of similar structures such as microaneurysms and hemorrhages, micro-vessel with only one to several pixels wide, and requirements for finer results. METHODS: In this paper, we present a multi-scale deeply supervised network with short connections (BTS-DSN) for vessel segmentation. We used short connections to transfer semantic information between side-output layers. Bottom-top short connections pass low level semantic information to high level for refining results in high-level side-outputs, and top-bottom short connection passes much structural information to low level for reducing noises in low-level side-outputs. In addition, we employ cross-training to show that our model is suitable for real world fundus images. RESULTS: The proposed BTS-DSN has been verified on DRIVE, STARE and CHASE_DB1 datasets, and showed competitive performance over other state-of-the-art methods. Specially, with patch level input, the network achieved 0.7891/0.8212 sensitivity, 0.9804/0.9843 specificity, 0.9806/0.9859 AUC, and 0.8249/0.8421 F1-score on DRIVE and STARE, respectively. Moreover, our model behaves better than other methods in cross-training experiments. CONCLUSIONS: BTS-DSN achieves competitive performance in vessel segmentation task on three public datasets. It is suitable for vessel segmentation. The source code of our method is available at: https://github.com/guomugong/BTS-DSN.


Assuntos
Vasos Retinianos/anatomia & histologia , Aprendizado de Máquina Supervisionado , Algoritmos , Fundo de Olho , Humanos
6.
BMC Ophthalmol ; 19(1): 27, 2019 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-30665394

RESUMO

BACKGROUND: Color fundus photography have been extensively used to explore the link between retinal morphology changes associated with various disease i.e. Diabetic Retinopathy, Glaucoma. The development of multimodal imaging system that integrates Infrared Scanning Laser Ophthalmoscope (IR-SLO) and Optical Coherence Tomography (OCT) could help in studying these diseases at an early stage. The aim of this study was to test the agreement between the retinal vasculature parameters from the Infrared images obtained from optical coherence tomography and color fundus imaging. METHODS: The IR and Color retinal images were obtained from 16 volunteer participants and seven retinal vessel parameters, i.e. Fractal Dimension (FD), Average Angle (ABA), Total Angle Count (TAC), Tortuosity (ST), Vessel/Background ratio (VBR), Central Retinal Arteriolar Equivalent (CRAE) and Central Retinal Venular Equivalent (CRVE) were extracted from these retinal images using Retinal Image Vasculature Assessment software (RIVAS) and Integrative Vessel Analysis (IVAN). RESULTS: The Bland Altman plot was used to investigate the agreement between the two modalities. The paired sample t-test was used to assess the presence of fixed bias and the slope of Least Square Regression (LSR) line for the presence of proportional bias. The paired sample t-test showed that there was no statistically significant difference between Color and IR based on retinal vessel features (all p values > 0.05). LSR also revealed no statistically significant difference in the retinal vessel features between Color and IR. CONCLUSION: This study has revealed that there is a fair agreement between Color and IR images based on retinal vessel features. This research has shown that it is possible to use IR images of the retina to measure the retinal vasculature parameters which has the advantage of being flash-less, can be used even if there is opacity due to cataract, and can be performed along with OCT on the same device.


Assuntos
Cor , Técnicas de Diagnóstico Oftalmológico , Fotografação/métodos , Vasos Retinianos/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Adulto , Técnicas de Diagnóstico Oftalmológico/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fotografação/normas , Análise de Regressão , Vasos Retinianos/anatomia & histologia , Tomografia de Coerência Óptica/normas , Adulto Jovem
8.
J Sci Med Sport ; 22(6): 672-676, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30553766

RESUMO

OBJECTIVES: To investigate the effect of combined aerobic and coordinative exercise on retinal microcirculation and its association with changes in cognitive performance in healthy adolescents. DESIGN: Using cluster-randomization (on class-level), 36 participants were allocated to an exercise group (EX) performing a 20-min aerobic and coordinative exercise session on each school day over a period of 8 weeks or a control group, which was encouraged to have social interactions (CON). METHOD: Prior to and following the intervention period, central retinal arteriolar (CRAE) and venular diameters (CRVE) were assessed by use of a static vessel analyzer. Additionally, a computer-based version of the Stroop Color-Word task was administered to assess inhibitory control. RESULTS: The statistical analysis revealed that EX compared to CON showed higher CRAE at post-test, when pre-test values were accounted for, F(1,32)=4.92, p=0.036, η2=0.130. In contrast, no such effect was reported for CRVE. With regard to cognitive performance, a greater reduction of reaction time on the Stroop task was observed in EX relative to CON, F(1,30)=8.58, p=0.006, η2=0.222. The increase in CRAE was significantly correlated with a decrease of reaction time on trials demanding inhibitory control, even after adjusting for covariates, r(31)=-0.438, p=0.011. CONCLUSIONS: A structured exercise program leads to a widening of retinal arteriolar diameters, which is associated with improvements in inhibitory control. Consequently, daily exercise sessions performed during the school break-time can be recommended for promoting both cardiovascular and cognitive health in adolescents.


Assuntos
Cognição , Exercício , Microcirculação , Educação Física e Treinamento , Adolescente , Criança , Feminino , Humanos , Masculino , Tempo de Reação , Vasos Retinianos/anatomia & histologia , Instituições Acadêmicas , Teste de Stroop
9.
Invest Ophthalmol Vis Sci ; 60(10): 3368-3373, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31917454

RESUMO

Purpose: The African American (AA) population has unique ocular anatomic characteristics and a disproportionately high incidence of glaucoma, which is associated with lower peripapillary vessel density (VD). This study aimed to identify ocular determinants of peripapillary VD in healthy AAs. Methods: This was a cross-sectional, population-based study of 1029 AAs, ages 40 and older. Participants underwent examination to obtain axial length (AL), IOP, central corneal thickness (CCT), mean retinal nerve fiber layer (RNFL) thickness, visual field mean deviation (MD), and 6 × 6-mm optical coherence tomography angiography scans of the optic nerve. Participants with glaucoma, vision-threatening diabetic retinopathy, or other relevant ocular disease were excluded. Prototype software was used to quantify VD. A multivariable regression model, controlling for age and signal strength, identified the ocular variables that predicted peripapillary VD. The contribution of each variable was assessed with the magnitude of standardized regression coefficients (SRC). Results: Based on univariate regressions, AL, RNFL thickness, and MD had significant associations with peripapillary VD (all P < 0.001). In the final multivariate model, lower mean RNFL thickness (ß = 0.0022, P < 0.001, SRC = 0.542) and longer AL (ß = -0.0055, P < 0.001, SRC = -0.118) were associated with lower peripapillary VD, controlling for age and signal strength, with model R2 of 0.69. Conclusions: Thinner RNFL and longer AL were the most influential ocular determinants of lower peripapillary perfusion in healthy AA eyes. Additional research is needed to clarify whether longer AL increases risk of glaucoma by affecting capillary perfusion.


Assuntos
Afro-Americanos , Disco Óptico/irrigação sanguínea , Vasos Retinianos/anatomia & histologia , Adulto , Comprimento Axial do Olho/anatomia & histologia , Estudos Transversais , Feminino , Angiofluoresceinografia , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Fibras Nervosas , Células Ganglionares da Retina/citologia , Tomografia de Coerência Óptica/métodos
10.
Invest Ophthalmol Vis Sci ; 59(15): 5847-5853, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30535425

RESUMO

Purpose: To differentiate the four layers of the retinal vessel network in the human macula and examine their morphologic features using high-resolution optical coherence tomography angiography (HR-OCTA). Methods: Macular areas measuring 464 × 464 pixels of 10 right eyes of 10 healthy subjects without ocular disease were scanned 10 times using a HR-OCTA device. Averaged OCTA images were created. Based on clear decorrelation signals, four vascular slabs were segmented, comprising one each in the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and top and bottom of the inner nuclear layer (INL). Qualitative features and quantitative measurements in each slab were compared with those in conventionally segmented slabs. Results: HR-OCTA isolated four layers of vascular plexuses in the macula that followed the corresponding anatomic layers. Segmentations for the RNFL revealed that radial peripapillary capillaries (RPCs) extended to the central macular area. The RPCs followed relatively straight and long paths, with few apparent feed points and anastomoses. The GCL slab enhanced visualization of the capillary-free zones around the arteries and arterioles and helped to differentiate arterial and venous systems. The arterioles and venules were linked by capillaries that were arranged in a mesh-like fashion, with multiple arteriolar feed points and anastomoses. Vascular plexuses in the top and bottom of the INL consisted of capillaries in a vortex arrangement. The center of these vortex arrangements was consistent with the venules in the GCL. Conclusions: HR-OCTA can differentiate the four layers of vascular plexuses in the human macula and elucidate their angiographic features.


Assuntos
Angiofluoresceinografia , Microcirculação/fisiologia , Vasos Retinianos/anatomia & histologia , Tomografia de Coerência Óptica , Adulto , Capilares/anatomia & histologia , Capilares/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fibras Nervosas , Estudos Prospectivos , Células Ganglionares da Retina/citologia , Vasos Retinianos/fisiologia
11.
Sao Paulo Med J ; 136(4): 276-286, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304202

RESUMO

BACKGROUND: Investigation of alterations to retinal microvasculature may contribute towards understanding the role of such changes in the pathophysiology of several chronic non-communicable diseases. The objective here was to evaluate the validity and reproducibility of retinal arteriole and venule diameter measurements made by Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) graders. DESIGN AND SETTING: Cross-sectional study at six teaching and research institutions. METHODS: To evaluate validity, each of 25 retinal images from the University of Wisconsin (gold standard) was measured by five ELSA-Brasil graders. To evaluate reproducibility, 105 images across the spectrum of vessel diameters were selected from 12,257 retinal images that had been obtained between 2010 and 2012, and each image was reexamined by the same grader and by an independent grader. All measurements were made using the Interactive Vessel Analysis (IVAN) software. Bland-Altman plots, paired t tests and intraclass correlation coefficients (ICCs) were analyzed. RESULTS: Mean differences between ELSA-Brasil and gold-standard readings were 0.16 µm (95% CI -0.17-0.50; P = 0.31) for central retinal artery equivalent (CRAE), -0.21 µm (95% CI -0.56-0.14; P = 0.22) for central retinal vein equivalent (CRVE) and 0.0005 (95% CI -0.008-0.009; P = 0.55) for arteriole/venule ratio (AVR). Intragrader ICCs were 0.77 (95% CI 0.67-0.86) for CRAE, 0.90 (95% CI 0.780.96) for CRVE and 0.70 (0.55-0.83) for AVR. Intergrader ICCs were 0.75 (95% CI 0.64-0.85) for CRAE, 0.90 (95% CI 0.79-0.96) for CRVE and 0.68 (95% CI 0.55-0.82) for AVR. CONCLUSIONS: Retinal microvascular diameter measurements are valid and present moderate to high intra and intergrader reproducibility in ELSA-Brasil.


Assuntos
Arteríolas/anatomia & histologia , Interpretação de Imagem Assistida por Computador , Vasos Retinianos/anatomia & histologia , Vênulas/anatomia & histologia , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores Socioeconômicos
12.
Invest Ophthalmol Vis Sci ; 59(11): 4327-4344, 2018 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-30193305

RESUMO

Purpose: To define the three-dimensional topologic organization of the human peripapillary capillary plexuses in order to better understand the hemodynamic characteristics of this retinal circulation. Methods: The retinal microvasculature was perfusion labeled in five normal human donor eyes, and optical stacks were collected from regions immediately superior, temporal, inferior, and nasal to the optic disk by using confocal scanning laser microscopy. The spatial location and morphometric characteristics of capillary plexuses were compared. Three-dimensional visualization strategies were used to document the organization of vascular conduits that interconnect capillary beds and to study the communications between capillary beds and precapillary arterioles and postcapillary venules. Results: The peripapillary microcirculation is composed of four capillary plexuses, including the radial peripapillary capillary plexus at the level of the nerve fiber layer, the superficial capillary plexus (SCP) at the level of the ganglion cell layer, the intermediate capillary plexus located at the inner boundary of the inner nuclear layer, and the deep capillary plexus located at the outer boundary of the inner nuclear layer. Capillary diameter and density were significantly different between the four plexuses (both P ≤ 0.011). The SCP is the only capillary bed that receives feeding and draining branches directly from precapillary arterioles and postcapillary venules, respectively. Four different inflow and outflow patterns characterized the communication between the SCP and surrounding capillary beds. Conclusions: The capillary plexuses of the human peripapillary microcirculation are arranged in series and parallel and manifest specializations that likely reflect the unique metabolic demands and biochemical environment of the retinal layers.


Assuntos
Capilares/anatomia & histologia , Imagem Tridimensional , Microcirculação/fisiologia , Disco Óptico/irrigação sanguínea , Vasos Retinianos/anatomia & histologia , Idoso , Capilares/diagnóstico por imagem , Feminino , Angiofluoresceinografia , Humanos , Microscopia Confocal , Vasos Retinianos/diagnóstico por imagem , Doadores de Tecidos , Tomografia de Coerência Óptica , Adulto Jovem
13.
Appl Opt ; 57(20): 5635-5642, 2018 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-30118075

RESUMO

The design and performance of an adaptive optics flood illumination ophthalmoscope (AO-FIO) platform, based on eye motion and dynamic aberrations experimental analysis, are described. The system incorporates a custom-built real-time controller, enabling up to 70 Hz loop rate without jitter, and an AO-corrected illumination capable of projecting high-resolution features in the retina. Wide-field (2.7°×5.4°) and distortionless images from vessel walls, capillaries, and the lamina cribrosa are obtained with an enhanced contrast and signal-to-noise ratio, thanks to careful control of AO parameters. The high spatial and temporal resolution (image acquisition up to 200 Hz) performance achieved by this platform enables the visualization of vessel deformation and blood flow. This system opens up the prospect of a return to favor of flood illumination adaptive optics systems provided that its high pixel rate and structured illumination capabilities are exploited.


Assuntos
Desenho de Equipamento , Luz , Oftalmoscópios , Óptica e Fotônica , Fluxo Sanguíneo Regional/fisiologia , Vasos Retinianos/anatomia & histologia , Feminino , Humanos , Masculino , Vasos Retinianos/fisiologia
14.
Invest Ophthalmol Vis Sci ; 59(10): 3858-3867, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30073360

RESUMO

Purpose: To assess the connection among arterioles, venules, and capillaries in three retinal capillary plexuses using optical coherence tomography angiography (OCTA). Methods: This was a prospective, cross-sectional, observational study including 20 eyes of 10 healthy subjects. En face and cross-sectional OCTA images were segmented to study the superficial (SCP), middle (MCP), and deep capillary plexuses (DCP). Using thin slabs and manual segmentation within the three plexuses, we examined the connections between the large-caliber superficial vessels within a 3 × 3 mm2 OCTA scan (arterioles and venules) and the smaller capillaries in each plexus. Results: Twenty eyes of 10 healthy subjects (5 females; average age of 30.8 ± 6.3 years) were included in the analysis. We identified vascular interconnections linking the superficial arterioles and venules with capillaries in each plexus (SCP, MCP, and DCP). We found capillaries in the DCP crossed the horizontal raphe. Conclusions: Our findings show that each of the three capillary plexuses in the parafovea has its own feeding arteriolar supply and draining venules, supporting a physiologic model in which each plexus controls its own oxygenated blood supply to match the metabolic needs of each distinct retinal neurovascular unit.


Assuntos
Capilares/anatomia & histologia , Fóvea Central/irrigação sanguínea , Vasos Retinianos/anatomia & histologia , Adulto , Estudos Transversais , Feminino , Angiofluoresceinografia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tomografia de Coerência Óptica , Adulto Jovem
15.
Public Health Nutr ; 21(14): 2642-2653, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29947308

RESUMO

OBJECTIVE: With the intention to inform future public health initiatives, we aimed to determine the extent to which typical childhood dietary trajectories predict adolescent cardiovascular phenotypes. DESIGN: Longitudinal study. Exposure was determined by a 4 d food diary repeated over eight waves (ages 4-15 years), coded by Australian Dietary Guidelines and summed into a continuous diet score (0-14). Outcomes were adolescent (Wave 8, age 15 years) blood pressure, resting heart rate, pulse wave velocity, carotid intima-media thickness, retinal arteriole-to-venule ratio. Latent class analysis identified 'typical' dietary trajectories from childhood to adolescence. Adjusted linear regression models assessed relationships between trajectories and cardiovascular outcomes, adjusted for a priori potential confounders. SETTING: Community sample, Melbourne, Australia. SUBJECTS: Children (n 188) followed from age 4 to 15 years. RESULTS: Four dietary trajectories were identified: unhealthy (8 %); moderately unhealthy (25 %); moderately healthy (46 %); healthy (21 %). There was little evidence that vascular phenotypes associated with the trajectories. However, resting heart rate (beats/min) increased (ß; 95 % CI) across the healthy (reference), moderately healthy (4·1; -0·6, 8·9; P=0·08), moderately unhealthy (4·5; -0·7, 9·7; P=0·09) and unhealthy (10·5; 2·9, 18·0; P=0·01) trajectories. CONCLUSIONS: Decade-long dietary trajectories did not appear to influence macro- or microvascular structure or stiffness by mid-adolescence, but were associated with resting heart rate, suggesting an early-life window for prevention. Larger studies are needed to confirm these findings, the threshold of diet quality associated with these physiological changes and whether functional changes in heart rate are followed by phenotypic change.


Assuntos
Fenômenos Fisiológicos Cardiovasculares , Dieta/tendências , Adolescente , Austrália , Pressão Sanguínea/fisiologia , Espessura Intima-Media Carotídea , Criança , Pré-Escolar , Frequência Cardíaca/fisiologia , Humanos , Estudos Longitudinais , Fenótipo , Análise de Onda de Pulso , Vasos Retinianos/anatomia & histologia , Fatores Socioeconômicos
16.
Med Biol Eng Comput ; 56(11): 2015-2024, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29740745

RESUMO

Normally, the optic disc detection of retinal images is useful during the treatment of glaucoma and diabetic retinopathy. In this paper, the novel preprocessing of a retinal image with a bat algorithm (BA) optimization is proposed to detect the optic disc of the retinal image. As the optic disk is a bright area and the vessels that emerge from it are dark, these facts lead to the selected segments being regions with a great diversity of intensity, which does not usually happen in pathological regions. First, in the preprocessing stage, the image is fully converted into a gray image using a gray scale conversion, and then morphological operations are implemented in order to remove dark elements such as blood vessels, from the images. In the next stage, a bat algorithm (BA) is used to find the optimum threshold value for the optic disc location. In order to improve the accuracy and to obtain the best result for the segmented optic disc, the ellipse fitting approach was used in the last stage to enhance and smooth the segmented optic disc boundary region. The ellipse fitting is carried out using the least square distance approach. The efficiency of the proposed method was tested on six publicly available datasets, MESSIDOR, DRIVE, DIARETDB1, DIARETDB0, STARE, and DRIONS-DB. The optic disc segmentation average overlaps and accuracy was in the range of 78.5-88.2% and 96.6-99.91% in these six databases. The optic disk of the retinal images was segmented in less than 2.1 s per image. The use of the proposed method improved the optic disc segmentation results for healthy and pathological retinal images in a low computation time. Graphical abstract ᅟ.


Assuntos
Algoritmos , Heurística , Disco Óptico/anatomia & histologia , Bases de Dados Factuais , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Disco Óptico/patologia , Doenças Retinianas/diagnóstico , Vasos Retinianos/anatomia & histologia , Vasos Retinianos/patologia , Retinoscopia/métodos
17.
Scand J Med Sci Sports ; 28(8): 1897-1907, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29701884

RESUMO

Our objective was to determine associations between retinal vascular caliber and physical activity (PA) in a school-based child cohort. In a prospective study, we created a childhood cumulative average PA-index using objectively measured PA (accelerometry) assessed at four periods between 2009 and 2015. Cumulative exposure to PA intensities was estimated. Cross-sectional examinations on biomarkers, anthropometry, and ophthalmological data including retinal fundus photographs were performed in 2015. Semi-automated measurements of retinal vascular diameters were performed and summarized into central retinal arteriolar and venular equivalents (CRAE, CRVE). We included 307 participants. Mean age in 2015 was 15.4 years (0.7). The mean CRAE and CRVE were 156.5 µm (2.8) and 217.6 µm (7.7), respectively. After adjusting for age, gender, and axial length, more time in PA was independently related to thinner retinal venules (ß-coefficient = -1.25 µm/%, 95% confidence interval = -2.20, -0.30, P < .01). Sedentary time was associated with wider venules (P < .01). Furthermore, birthweight (ß-coefficient = 0.56 µm/%, 95% confidence interval = 0.18, 0.95, P < .01) was associated with CRVE. Blood pressure was associated with thinner retinal arterioles (ß-coefficient = -0.19 µm/mmHg, 95% confidence interval = -0.36, -0.01, P = .04). We concluded that children with higher PA in childhood had thinner retinal venular caliber. Our results suggest that PA during childhood positively impacts the retinal microcirculation and that retinal vascular analysis may be a possible assessment to detect microvascular impairments in children with an increased risk of future cardiovascular disease.


Assuntos
Exercício , Vasos Retinianos/anatomia & histologia , Adolescente , Arteríolas/anatomia & histologia , Estudos Transversais , Dinamarca , Feminino , Humanos , Estudos Longitudinais , Masculino , Microcirculação , Fotografação , Estudos Prospectivos , Vênulas/anatomia & histologia
18.
Methods Mol Biol ; 1753: 317-330, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29564799

RESUMO

The retina is a highly organized neural tissue consisting of three neural layers and two synaptic layers. Blood vessels that nourish the mouse and human neural retina mirror this organization consisting of three plexus layers, or plexuses, that run parallel within the retina, connected by interplexus vessels to create a closed vascular network. Here, we describe a methodology to describe this organization that can be used to interrogate factors mediating retinal vessel patterning including: coverage of the vascular plexuses, branching and orientation of the interplexus connections, and digital reconstruction of the retinal vasculature to measure vessel length and density. The methodology focuses on the mouse retina, but can easily be adapted to study retinal vessels of other species.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Retina/diagnóstico por imagem , Vasos Retinianos/diagnóstico por imagem , Animais , Processamento de Imagem Assistida por Computador/instrumentação , Camundongos , Microscopia/instrumentação , Microscopia/métodos , Retina/anatomia & histologia , Vasos Retinianos/anatomia & histologia , Software , Coloração e Rotulagem/instrumentação , Coloração e Rotulagem/métodos
19.
J Clin Periodontol ; 45(4): 404-412, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29385643

RESUMO

AIM: To investigate the relation between oral health status and microcirculation, we analysed the association between periodontitis and number of teeth with retinal vessel diameters in a population-based study. METHODS: We analysed data from the Study of Health in Pomerania-TREND (SHIP-TREND). All subjects (3,183 for number of teeth, 3,013 for mean probing depth and 2,894 for mean attachment level) underwent nonmydriatic funduscopy and dental examination. We measured central retinal arteriolar (CRAE), venular (CRVE) vessel diameters and calculated arterio-venous ratio (AVR) from static vessel analysis (SVA). Periodontal status was assessed using the case definition of the Center for Disease Control and Prevention/American Academy of Periodontology (CDC/AAP). Data were analysed by linear (CRAE, CRVE, AVR) and logistic regression (AVR < 0.8) adjusted for age, sex, smoking status, alcohol consumption, body mass index, systolic blood pressure, hsCRP and type-2-diabetes mellitus. RESULTS: Only in men, significant associations were found between periodontal and retinal conditions. Severe periodontitis [ß = -0.0120 (-0.0218; -0.0007 95%-CI)] and mean probing depth [ß = -0.0054 (-0.0105; -0.0002 95%-CI)] were inversely associated with AVR; severe periodontitis [ß = 3.80 (0.61; 6.98 95%-CI)], mean probing depth [ß = 1.86 (0.23; 3.49 95%-CI)] and mean attachment level [ß = 1.31 (0.34; 2.27 95%-CI)] with CRVE and mean attachment level with CRAE [ß = 0.91 (0.14; 1.69 95%-CI)]. CONCLUSIONS: Our results point towards an association between periodontal conditions and AVR in men. Periodontitis may impact microvascular endothelium function. Improving oral health to reduce periodontitis might lead to reduced risk for other age-related diseases.


Assuntos
Periodontite Crônica/fisiopatologia , Saúde Bucal , Vasos Retinianos/fisiopatologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Microcirculação/fisiologia , Pessoa de Meia-Idade , Índice Periodontal , Bolsa Periodontal , Vasos Retinianos/anatomia & histologia , Vasos Retinianos/diagnóstico por imagem , Fatores Sexuais , Perda de Dente
20.
PLoS One ; 13(2): e0191434, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29389952

RESUMO

PURPOSE: Childhood obesity is associated with adult cardiometabolic disease. We postulate that the underlying microvascular dysfunction begins in childhood. We thus aimed to compare retinal vascular parameters between obese and non-obese children. METHODS: This was a cross-sectional study involving 166 children aged 6 to 12 years old in Malaysia. Ocular examination, biometry, retinal photography, blood pressure and body mass index measurement were performed. Participants were divided into two groups; obese and non-obese. Retinal vascular parameters were measured using validated software. RESULTS: Mean age was 9.58 years. Approximately 51.2% were obese. Obese children had significantly narrower retinal arteriolar caliber (F(1,159) = 6.862, p = 0.010), lower arteriovenous ratio (F(1,159) = 17.412, p < 0.001), higher venular fractal dimension (F(1,159) = 4.313, p = 0.039) and higher venular curvature tortuosity (F(1,158) = 5.166, p = 0.024) than non-obese children, after adjustment for age, gender, blood pressure and axial length. CONCLUSIONS: Obese children have abnormal retinal vascular geometry. These findings suggest that childhood obesity is characterized by early microvascular abnormalities that precede development of overt disease. Further research is warranted to determine if these parameters represent viable biomarkers for risk stratification in obesity.


Assuntos
Obesidade/patologia , Vasos Retinianos/anatomia & histologia , Estudos de Casos e Controles , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Estudos Prospectivos , Vasos Retinianos/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA