Noninvasive Visualization and Analysis of Parafoveal Capillaries in Humans

Tam, Johnny; Martin, Justin F.; Roorda, Austin

doi:10.1167/iovs.09-4483

Cited by 185 publications

(186 citation statements)

References 22 publications

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“…However, there is no convincing evidence to support these differences. [21][22][23] Another predictor of better anatomical response to laser treatment is the morphological subtype of the oedema on OCT. The morphological categories of our Qualitative and quantitative OCT response to macular laser photocoagulation R Vemala et al cohort with diffuse macular oedema showed that 57% were DRT, whereas 37% were cystoid in keeping with the observations of Brar et al 24 On correlating the angiographic and OCT appearance of DMO, they observed that angiographic evidence of diffuse macular oedema is most often associated with DRT on OCT, although microcysts are common, whereas cystoid leakage on fluorescein angiography is always associated with cystic changes on spectral domain OCT.…”

Section: Discussionmentioning

confidence: 99%

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Vemala

Koshy

Sivaprasad

2011

Eye

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Purpose To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT). Patients and Methods Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB). Results The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300-350 lm had the worst response (þ 0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (À0.33 ETDRS letters). Conclusion The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.

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Section: Discussionmentioning

confidence: 99%

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Vemala

Koshy

Sivaprasad

2011

Eye

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“…23,33 Recently, parafoveal capillaries were visualized with advanced video processing techniques in AOSLO. 34 These motion contrast methods use the change in reflectance caused by blood flowing through the vessels (that is, the variance in the image) to map vessel paths. Tam et al 34 have shown that this technique can reveal the smallest vessels in a way that is superior to conventional fluorescein angiography and with vessel resolution that is comparable to that seen using FAOSLO.…”

Section: Retinal Vasculaturementioning

confidence: 99%

“…34 These motion contrast methods use the change in reflectance caused by blood flowing through the vessels (that is, the variance in the image) to map vessel paths. Tam et al 34 have shown that this technique can reveal the smallest vessels in a way that is superior to conventional fluorescein angiography and with vessel resolution that is comparable to that seen using FAOSLO. 21,33 The greatest advantage of this method over fluorescein angiography is that this technique can be done non-invasively and repeatedly, in both normal and diseased eyes.…”

Section: Retinal Vasculaturementioning

confidence: 99%

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Imaging retinal mosaics in the living eye

Rossi

Chung

Dubra

et al. 2011

Eye

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Adaptive optics imaging of cone photoreceptors has provided unique insight into the structure and function of the human visual system and has become an important tool for both basic scientists and clinicians. Recent advances in adaptive optics retinal imaging instrumentation and methodology have allowed us to expand beyond cone imaging. Multi-wavelength and fluorescence imaging methods with adaptive optics have allowed multiple retinal cell types to be imaged simultaneously. These new methods have recently revealed rod photoreceptors, retinal pigment epithelium (RPE) cells, and the smallest retinal blood vessels. Fluorescence imaging coupled with adaptive optics has been used to examine ganglion cells in living primates. Two-photon imaging combined with adaptive optics can evaluate photoreceptor function non-invasively in the living primate retina.

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“…Motion contrast perfusion maps were then generated to highlight the parafoveal capillary network. This motion contrast technique is similar to what was used by Tam et al [19], but with the AOSLO focus set at the plane of the retinal vasculature using multiply scattered light imaging [17] rather than at the plane of the photoreceptors for direct visualization of BCA movement and more precise rendering of the vessel lumen boundaries. Ten frames with the largest intensity variations were selected from the 50 frame video to calculate the perfusion map on a pixel-by-pixel basis.…”

Section: Image Processing and Luminal Surface Reconstructionmentioning

confidence: 99%

Computational fluid dynamics assisted characterization of parafoveal hemodynamics in normal and diabetic eyes using adaptive optics scanning laser ophthalmoscopy

Bernabéu¹,

Lammer²,

Cai³

et al. 2016

Biomed. Opt. Express

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Diabetic retinopathy (DR) is the leading cause of visual loss in working-age adults worldwide. Previous studies have found hemodynamic changes in the diabetic eyes, which precede clinically evident pathological alterations of the retinal microvasculature. There is a pressing need for new methods to allow greater understanding of these early hemodynamic changes that occur in DR. In this study, we propose a noninvasive method for the assessment of hemodynamics around the fovea (a region of the eye of paramount importance for vision). The proposed methodology combines adaptive optics scanning laser ophthalmoscopy and computational fluid dynamics modeling. We compare results obtained with this technique with in vivo measurements of blood flow based on blood cell aggregation tracking. Our results suggest that parafoveal hemodynamics, such as capillary velocity, wall shear stress, and capillary perfusion pressure can be noninvasively and reliably characterized with this method in both healthy and diabetic retinopathy patients.

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Noninvasive Visualization and Analysis of Parafoveal Capillaries in Humans

Abstract: Using motion cues to enhance vessel contrast is a powerful tool for visualizing the capillary network, in the absence of contrast agents. The authors demonstrate a tool to study the microcirculation of healthy subjects noninvasively.

Cited by 185 publications

References 22 publications

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Imaging retinal mosaics in the living eye

Computational fluid dynamics assisted characterization of parafoveal hemodynamics in normal and diabetic eyes using adaptive optics scanning laser ophthalmoscopy

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