Influence of refractive error and axial length on retinal vessel geometric characteristics

L, Lim; Cheung, Carol Y.; Lim, Xian Hui; Mitchell, Paul; Ty, Wong; Saw, S. M.

doi:10.1111/j.1755-3768.2013.4676.x

Cited by 10 publications

(13 citation statements)

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“…Recent studies have demonstrated an association between narrowing of retinal arteriolar caliber and spherical equivalent using retinal photography and measurement of retinal vascular calibers and suggested that myopia might have an effect on retinal microvasculature (20,22). It is known that refractive errors are due to elongation of the eyeball are typical in myopic subjects.…”

Section: Discussionmentioning

confidence: 99%

“…By the increase of SE in myopic subjects, the axis also elongates since the myopic subjects have larger bulbi and the axial length and refraction share common genes in their etiology (5,17). This mechanical stretching and thinning of the choroid and retinal pigment epithelium with accompany with concomitant vascular and degenerative changes such as reduction of retinal blood flow velocity and decreased retinal vascular caliber and retinal vessel geometry (20,21,22,34,35). According to our finding, this volume-pressure association has no effect on the investigated systemic hemodynamic parameters, neither on augmentation index (peripheral vascular resistance) nor on systemic arterial stiffness (PWV) and other pressure values measured by oscillometry.…”

Section: Discussionmentioning

confidence: 99%

“…Essential arterial hypertension was strongly associated with hypermetropia in a Turkish study (15), however, another study showed no relationship (8). Several studies have shown an association between narrowing of retinal arteriolar caliber and refractive error (either spherical equivalent or axial length) in children and adults suggesting that myopia might have an effect on retinal microvasculature (20,22). Although new risk factors have been determined in 2007 Guidelines for the Management of Arterial Hypertension including increased arterial stiffness (27), the association of this novel hemodynamic parameter and refraction of the eye has never been investigated.…”

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confidence: 95%

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Genetic effects on refraction and correlation with hemodynamic variables: A twin study

Toth¹,

Tárnoki²,

Tárnoki³

et al. 2014

Acta Physiologica Hungarica

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Spherical equivalent (SE) has not been linked to increased cardiovascular morbidity. Methods: 132 Hungarian twins (age 43.3±16.9 years) underwent refraction measurements (Huvitz MRK-3100 Premium AutoRefractokeratometer) and oscillometry (TensioMed Arteriograph). Results: Heritability analysis indicated major role for genetic components in the presence of right and left SE (82.7%, 95%CI, 62.9 to 93.7%, and 89.3%, 95%CI, 72.8 to 96.6%), while unshared environmental effects accounted for 17% (95%CI, 6.3% to 37%), and 11% (95%CI, 3.4% to 26.7%) of variations adjusted for age and sex. Bilateral SE showed weak age-dependent correlations with augmentation index (AIx), aortic pulse wave velocity (r ranging between 0.218 and 0.389, all p < 0.01), aortic systolic blood pressure and pulse pressure (r between 0.188 and 0.289, p < 0.05). Conclusions: These findings support heritability of spherical equivalent, which does not coexist with altered hemodynamics (e.g. accelerated arterial aging). Accordingly, SE and the investigated hemodynamic parameters seem neither phenotypically nor genetically associated.Keywords: arterial stiffness, augmentation index, genetics, heritability, refractionThe first "twin study" was published in 1922 by Walter Jablonski, the first ophthalmologist who used both monozygotic and dizygotic twins to examine the factors that determine the development of the refraction of the eye. He declared "the smaller differences are seen in the majority of monozygotic cases, while larger differences occur in dizygotic cases" (23).Since then, numerous articles discussed the role of inheritance, the genetic predisposition and the gene-environment interactions taking part in the formation of the refractive characteristics of the eye confirming that genetic factors account for 77-94% of the genetic variance (10,25,26,43). However, a similar study in a wide-age range sample is still needed. In addition, despite heritability of refraction was thoroughly investigated in the studies *These authors contributed equally to this work.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 95%

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Genetic effects on refraction and correlation with hemodynamic variables: A twin study

Toth¹,

Tárnoki²,

Tárnoki³

et al. 2014

Acta Physiologica Hungarica

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“…Alterations in ocular shape, as it occurs for example in myopia, are often associated with vascular abnormalities [5,34,42] and with higher risks of severe ocular conditions, such as glaucoma [18,30], retinal detatchment [32,50] and maculopathy [17,27]. Architectural changes in the retinal vasculature are also often associated with ocular diseases, including glaucoma [22,29,46,48], diabetic retinopathy [9,8,24] and myopia [16,31].…”

Section: Introductionmentioning

confidence: 99%

Effect of ocular shape and vascular geometry on retinal hemodynamics: a computational model

Dziubek

Guidoboni

Harris

et al. 2015

Biomech Model Mechanobiol

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Thistleton, W. (2016Effect of ocular shape and vascular geometry on retinal hemodynamics: a computational modelReceived: date / Accepted: date Abstract A computational model for retinal hemodynamics accounting for ocular curvature is presented. The model combines: (i) a hierarchical Darcy model for the flow through small arterioles, capillaries and small venules in the retinal tissue, where blood vessels of different size are comprised in different hierarchical levels of a porous medium; and (ii) a one-dimensional network model for the blood flow through retinal arterioles and venules of larger size. The non-planar ocular shape is included by: (i) defining the hierarchical Darcy flow model on a two-dimensional curved surface embedded in the three-dimensional space; and (ii) mapping the simplified one-dimensional network model onto the curved surface. The model is solved numerically using a finite element method in which spatial domain and hierarchical levels are discretized separately. For the finite element method we use an exterior calculus based implementation which permits an easier treatment of non-planar domains. Numerical solutions are verified against suitably constructed analytical solutions. Numerical experiments are performed to investigate how

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“…Degeneration of retinal vessel walls and changes in their elastic properties have been identified to be major causes of vessel tortuosity (Azegrouz et al;. The duration of diabetic disease has a strong effect on changes in vessel tortuosity (Lim et al;Sasongko et al;.…”

Section: Introductionmentioning

confidence: 99%

Automatic Retinal Vessel Detection and Tortuosity Measurement

Mapayi¹,

Tapamo²,

Viriri³

et al. 2016

Image Anal Stereol

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As retinopathies continue to be major causes of visual loss and blindness worldwide, early detection and management of these diseases will help achieve significant reduction of blindness cases. However, an efficient automatic retinal vessel segmentation approach remains a challenge. Since efficient vessel network detection is a very important step needed in ophthalmology for reliable retinal vessel characterization, this paper presents the study on the combination of difference image and k-means clustering for the segmentation of retinal vessels. Stationary points in the vessel center-lines are used to model the detection of twists in the vessel segments. The combination of arc-chord ratio with stationary points is used to compute tortuosity index. Experimental results show that the proposed k-means combined with difference image achieved a robust segmentation of retinal vessels. A maximum average accuracy of 0.9556 and a maximum average sensitivity of 0.7581 were achieved on DRIVE database while a maximum average accuracy of 0.9509 and a maximum average sensitivity of 0.7666 were achieved on STARE database. When compared with the previously proposed techniques on DRIVE and STARE databases, the proposed technique yields higher mean sensitivity and mean accuracy rates in the same range of very good specificity. In a related development, a non-normalized tortuosity index that combined distance metric and the vessel twist frequency proposed in this paper also achieved a strong correlation of 0.80 with the expert ground truth.

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Influence of refractive error and axial length on retinal vessel geometric characteristics

Cited by 10 publications

References 0 publications

Genetic effects on refraction and correlation with hemodynamic variables: A twin study

Genetic effects on refraction and correlation with hemodynamic variables: A twin study

Effect of ocular shape and vascular geometry on retinal hemodynamics: a computational model

Automatic Retinal Vessel Detection and Tortuosity Measurement

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