Full anterior segment biometry with extended imaging range spectral domain optical coherence tomography at 1340 nm

Johnstone, Murray; Wang, Ke

doi:10.1117/1.jbo.19.4.046013

Cited by 32 publications

(21 citation statements)

References 59 publications

(102 reference statements)

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“…OCT is, in fact, currently being explored to investigate the AOS in animal 15,16 and human eyes. [17][18][19][20][21][22][23][24][25] Several OCT studies have shown the correlation between cross-sectional SC area and IOP, consistent with previous findings of pressure-dependent movement in ex vivo human and nonhuman primate (NHP) eyes using a morphometric analysis system. 26 For example, the SC area has been shown to decrease in response to acute change in IOP in healthy human subjects.…”

Section: Introductionsupporting

confidence: 67%

Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

et al. 2014

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Abstract. The aqueous outflow system (AOS) is responsible for maintaining normal intraocular pressure (IOP) in the eye. Structures of the AOS have an active role in regulating IOP in healthy eyes and these structures become abnormal in the eyes with glaucoma. We describe a newly developed system platform to obtain high-resolution images of the AOS structures. By incorporating spectral domain optical coherence tomography (SD-OCT), the platform allows us to systematically control, image, and quantitate the responses of AOS tissue to pressure with a millisecond resolution of pulsed flow. We use SD-OCT to image radial limbal segments from the surface of the trabecular meshwork (TM) with a spatial resolution of ∼5 μm in ex vivo nonhuman primate eyes. We carefully insert a cannula into Schlemm's canal (SC) to control both pressures and flow rates. The experimental results demonstrate the capability of the platform to visualize the unprecedented details of AOS tissue components comparable to that delivered by scanning electron microscopy, as well as to delineate the complex pressure-dependent relationships among the TM, structures within the SC, and collector channel ostia. The described technique provides a new means to characterize the anatomic and pressure-dependent relationships of SC structures, particularly the active motion of collagenous elements at collector channel ostia; such relationships have not previously been amenable to study. Experimental findings suggest that continuing improvements in the OCT imaging of the AOS may provide both insights into the glaucoma enigma and improvements in its management.

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Section: Introductionsupporting

confidence: 67%

Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

et al. 2014

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“…Such an approach has enabled discovery of previously overlooked valve-like elements in human eyes. 38,39 …”

Section: Discussionmentioning

confidence: 99%

Quantification of Focal Outflow Enhancement Using Differential Canalograms

Loewen

Brown

Scott

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PurposeTo quantify regional changes of conventional outflow caused by ab interno trabeculectomy (AIT).MethodsGonioscopic, plasma-mediated AIT was established in enucleated pig eyes. We developed a program to automatically quantify outflow changes (R, package eye-canalogram, github.com) using a fluorescent tracer reperfusion technique. Trabecular meshwork (TM) ablation was demonstrated with fluorescent spheres in six eyes before formal outflow quantification with two-dye reperfusion canalograms in six additional eyes. Eyes were perfused with a central, intracameral needle at 15 mm Hg. Canalograms and histology were correlated for each eye.ResultsThe pig eye provided a model with high similarity to AIT in human patients. Histology indicated ablation of TM and unroofing of most Schlemm's canal segments. Spheres highlighted additional circumferential and radial outflow beyond the immediate area of ablation. Differential canalograms showed that AIT caused an increase of outflow of 17 ± 5-fold inferonasally, 14 ± 3-fold superonasally, and also an increase in the opposite quadrants with a 2 ± 1-fold increase superotemporally, and 3 ± 3 inferotemporally. Perilimbal specific flow image analysis showed an accelerated nasal filling with an additional perilimbal flow direction into adjacent quadrants.ConclusionsA quantitative, differential canalography technique was developed that allows us to quantify supraphysiological outflow enhancement by AIT.

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“…Automated segmentation algorithms are under development (Dastiridou, A et al IOVS 2016; ARVO Abstract 5119-C0134). In particular, phase-based OCT has shown dynamic motion in TM and post-TM outflow pathways with demonstration of a pulsatile tempo likely related to the cardiac cycle 13–17 .…”

Section: Introductionmentioning

confidence: 99%

Aqueous Angiography in Living Nonhuman Primates Shows Segmental, Pulsatile, and Dynamic Angiographic Aqueous Humor Outflow

Huang

Yang

et al. 2017

Ophthalmology

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Purpose To evaluate the feasibility of safely performing aqueous angiography in intact eyes of living non-human primates (NHPs) for evaluating aqueous humor outflow and segmental patterns. Methods Aqueous angiography was performed in 6 non-human primates. After anesthesia, an anterior chamber (AC) maintainer was placed through a temporal 1 mm side-port wound. Indocyanine green (ICG; 0.4%) or 2.5% fluorescein was introduced (individually or in sequence) into the eye with a gravity-driven constant-pressure system. Aqueous angiography images were obtained with a Spectralis HRA+OCT (Heidelberg Engineering) suspended over the NHP eye using a custom designed surgical boom arm. Concurrent anterior segment optical coherence tomography (OCT) was performed on distally angiographically positive and negative regions. Results Aqueous angiography in the living NHP eye demonstrated mostly stable angiographic patterns. With multi-modal imaging, angiographically positive signal co-localized with episcleral veins as identified by infrared imaging and intrascleral lumens as demonstrated by anterior segment OCT. Sequential aqueous angiography in individual eyes with ICG followed by fluorescein showed similar angiographic patterns. A pulsatile nature of aqueous angiographic outflow was sometimes observed. Aqueous angiographic patterns could also dynamically change. In some instances, positive angiographic flow suddenly arose in regions previously without angiographic signal. Alternatively, angiographic signal could suddenly disappear from regions in which angiographic signal was initially documented. Discussion Aqueous angiography in living NHPs demonstrated segmental and pulsatile patterns with a newly described ability to dynamically shift. These characteristics further the understanding of live aqueous humor outflow biology and maybe useful in improving glaucoma surgeries aimed at trabecular meshwork bypass.

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Full anterior segment biometry with extended imaging range spectral domain optical coherence tomography at 1340 nm

Cited by 32 publications

References 59 publications

Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

Quantification of Focal Outflow Enhancement Using Differential Canalograms

Aqueous Angiography in Living Nonhuman Primates Shows Segmental, Pulsatile, and Dynamic Angiographic Aqueous Humor Outflow

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