Intraocular and Interocular Symmetry in Normal Retinal Capillary Perfusion

Rawji, M; Flanagan, John G.

doi:10.1097/00061198-200102000-00003

Cited by 15 publications

(16 citation statements)

References 15 publications

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“…Interestingly, blood flow was found to be reduced in patients with exudative maculopathy in comparison with patients with no, preproliferative, or proliferative, diabetic retinopathy. Rawji and Flanagan 22 recently reported the magnitude of intraocular and interocular asymmetry of SLDF derived retinal blood flow parameters in clinically normal volunteers. As anticipated, capillary perfusion was found to increase with eccentricity from the fovea and no significant interocular asymmetry was observed.…”

Section: Discussionmentioning

confidence: 99%

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema

Hudson

Flanagan²,

Turner³

et al. 2005

British Journal of Ophthalmology

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Aims: To compare the macular capillary blood flow of patients with clinically significant diabetic macular oedema (DMO) with that of non-diabetic subjects and to determine the relation between blood flow and capillary leakage in patients with DMO. Methods: The sample comprised 45 non-diabetic subjects (mean age 59 years) and 18 type 2 patients with clinically significant DMO (mean age 60 years). Macular capillary blood flow measurements were acquired using the Heidelberg retina flowmeter (HRF) and a 10˚62.5˚scan field centred on the fovea. Fluorescein angiography was undertaken on each of the diabetic patients after the completion of HRF measurements. Results: Temporal macular capillary blood flow was significantly lower for the patients with clinically significant DMO compared with age matched non-diabetic subjects (ANCOVA, p = 0.0011) while relative nasal-temporal asymmetry of macular capillary blood flow was significantly higher (p = 0.0125). Nasal-temporal asymmetry of macular capillary blood flow was significantly higher for the patients with DMO and capillary leakage within the scan area (two tailed t test, p = 0.0071). Macular capillary blood flow was always lower in areas of DMO and capillary leakage. Conclusion: Capillary blood flow was reduced in areas of DMO and capillary leakage, suggesting the presence of a localised perturbation of capillary blood flow regulation. R etinal capillaries lack an autonomic nerve supply but they are thought to have an intrinsic ability to constrict or dilate-that is, autoregulate, in order to ensure adequate blood flow to retinal tissues under changing conditions. 1 In addition, autoregulation is thought to be primarily facilitated by the vascular reactivity of upstream arterioles. Disturbance of retinal capillary blood flow is a feature of many ocular diseases, including diabetic retinopathy and glaucoma. A number of non-invasive instruments have been designed to measure retinal haemodynamics. 2-5Scanning laser Doppler flowmetry (SLDF-that is, the combination of a laser Doppler flowmeter and a scanning laser system) is unique in that it provides a two dimensional quantifiable perfusion map of retinal capillary blood flow rather than a measurement of flow at a single point.6 SLDF has potential as a clinical tool to non-invasively visualise and quantify retinal capillary blood flow. [6][7][8] Retinal capillary blood flow disturbance is fundamental to the pathogenesis of diabetic retinopathy. However, retinal blood flow as measured in the major retinal vessels of patients with diabetic retinopathy is reported by some to be reduced 9-11 and by others to be increased 1 12-14 when compared to non-diabetic subjects, in part depending on the severity of the retinopathy or on the heterogeneity of the group. This study focuses on diabetic patients with diabetic macular oedema (DMO) and on the macular capillary circulation. Macular oedema is the leading cause of visual impairment and legal blindness in people with diabetes. 15 To the best of our knowledge, no studies have investi...

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Section: Discussionmentioning

confidence: 99%

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema

Hudson

Flanagan²,

Turner³

et al. 2005

British Journal of Ophthalmology

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“…cant [10] . In our study, the right to left ratio (r/l ratio) of macular blood flow in controls approached to unity, indicating that the intereye difference of retinal blood flow in a single subject was not significant.…”

Section: Discussionmentioning

confidence: 99%

“…Although the interindividual variation of retinal blood flow was reported to be high, the intereye difference within each subject was insignificant [8][9][10] . Therefore, the intereye difference of retinal blood flow measured with HRF can be used as a reliable index for unilateral retinal diseases.…”

Section: Introductionmentioning

confidence: 99%

Macular Capillary Blood Flow in Patients with Diffuse Diabetic Macular Edema without Vitreomacular Traction

Park¹,

Woo²,

Ha³

et al. 2009

Ophthalmic Res

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Background: To evaluate macular microcirculation in patients with unilateral diffuse diabetic macular edema (DME) in order to determine whether the alteration in macular microcirculation is associated with development of diffuse DME without vitreomacular traction. Methods: According to the presence of epiretinal membrane (ERM), 27 patients having unilateral diffuse DME were divided into DME without ERM (non-ERM-DME group, n = 12) and with ERM (ERM-DME group, n = 15). Twelve patients with macular edema associated with unilateral branch vein obstruction (BVO) and 10 nondiabetic healthy subjects were enrolled as controls. Macular blood flow measured by Heidelberg retinal flowmeter was compared between the edematous eye and the nonedematous fellow eye of each patient and between groups. The macular thickness was evaluated with optical coherence tomography. Results: The mean macular blood flow was significantly higher than that of the contralateral eyes in edematous eyes of non-ERM-DME group (798.8 vs. 379.8 AU, p < 0.001). By contrast, in the ERM-DME group, the mean macular blood flow of DME eyes was similar to that of fellow eyes (575.9 vs. 596.4 AU, p = 0.538). The macular capillary blood flow in patients with BVO was not significantly different compared with nondiabetic controls (p = 0.967). Conclusions: The results suggest that the alteration of macular microcirculation may play a role in the pathogenesis of diffuse DME without vitreomacular traction.

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“…It was shown that up to 30% of normal eyes have preretinal glial membrane at postmortem [20] and the majority (70%) of eyes with macular hole appears do not have significant visible membrane around the edge of the hole [7]. Macula is vascularized by a three-layered capillary network that gradually decreases in number to the capillary free zone which is around 350-450 lm in the foveola [12,21]. Capillary volume is found to be significantly lower in the foveola than in other retinal areas [12].…”

Section: Discussionmentioning

confidence: 99%

“…SLDF uses the optic Doppler effect to measure the amount and velocity of moving red blood cells. The spatial resolution of the system is approximately 10 mm 2 [12] and the thickness of the imaged layer is approximately 400 lm [13].…”

Section: Methodsmentioning

confidence: 99%

Foveolar Choroidal Blood Flow in Idiopathic Macular Hole

2004

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Although, it may be result of macular hole, not necessarily the cause of it, these findings suggest that the eyes with idiopathic macular hole are associated with reduced foveolar blood flow. The measurement of the foveolar blood flow from choriocapillaris may be useful for identifying the subjects who have increased risk of development of macular hole in future. The study showed the association of a decrease in foveolar choroidal blood flow in eyes with idiopathic macular hole using HRF. Authors suggested that quantitative measurement of foveolar choroidal blood flow may be helpful for identifying the subjects who have increased risk of development of idiopathic macular hole.

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Intraocular and Interocular Symmetry in Normal Retinal Capillary Perfusion

Cited by 15 publications

References 15 publications

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema

Macular Capillary Blood Flow in Patients with Diffuse Diabetic Macular Edema without Vitreomacular Traction

Foveolar Choroidal Blood Flow in Idiopathic Macular Hole

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