Characterization of Uveoscleral Outflow in Enucleated Porcine Eyes Perfused under Constant Pressure

Wagner, Justin A.; Edwards, Aure ́lie; Schuman, Joel S.

doi:10.1167/iovs.03-1176

Cited by 19 publications

(9 citation statements)

References 18 publications

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“…After blocking the conventional pathway of drainage, the drainage declined at an average rate of 1.1±0.5 μl/min. However, blocking the vortex veins does not change the uveoscleral drainage, which is maintained at 1.2±0.8 μl/min [24].…”

Section: Uveoscleral Drainagementioning

confidence: 88%

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The parameters of the porcine eyeball

Sánchez

Martín

Ussa

et al. 2011

Graefes Arch Clin Exp Ophthalmol

237

136

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Section: Uveoscleral Drainagementioning

confidence: 88%

“…The study of Wagner et al [24] using enucleated porcine eyes showed that uveoscleral drainage contributes to the total drainage of the aqueous humour and that the choroid does not represent a significant pathway for uveoscleral drainage.…”

Section: Ciliary Bodymentioning

confidence: 99%

The parameters of the porcine eyeball

Sánchez

Martín

Ussa

et al. 2011

Graefes Arch Clin Exp Ophthalmol

237

136

View full text Add to dashboard Cite

show abstract

“…The proportion of the total flow for the entire analysis region excluding the cornea or anterior segment compression ring was then attributed to each quadrant and converted to units of microliters per minute using the established flow of 3 microliters per minute (see example in S1 Fig ). [ 24 ]…”

Section: Methodsmentioning

confidence: 99%

Regionally Discrete Aqueous Humor Outflow Quantification Using Fluorescein Canalograms

et al. 2016

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PurposeTo visualize and quantify conventional outflow directly in its anatomic location.MethodsWe obtained fluorescein canalograms in six porcine whole eyes and six porcine anterior segment cultures. Eyes were perfused with a constant pressure of 15 mmHg using media containing 0.017 mg/ml fluorescein. Flow patterns were visualized using a stereo dissecting microscope equipped for fluorescent imaging. Images were captured every 30 seconds for 20 minutes for time lapse analysis. Anterior chamber cultures were imaged again on day three of culture. Canalograms were first analyzed for filling time per quadrant. We then wrote a program to automatically compute focal flow fits for each macropixel and to detect convergent perilimbal flow patterns with macropixels grouped into 3 equal-radial width rings around the cornea. A generalized additive model was used to determine fluorescence changes of individual macropixels.ResultsThe resulting imaging algorithm deployed 1024 macropixels that were fit to determine maximum intensity and time to fill. These individual fits highlighted the focal flow function. In whole eyes, significantly faster flow was seen in the inferonasal (IN) and superonasal (SN) quadrants compared to the superotemporal (ST) and inferotemporal (IT) ones (p<0.05). In anterior chamber cultures, reduced flow on day 1 increased in all quadrants on day 3 except in IT (p<0.05). Perilimbal ring analysis uncovered convergent perilimbal flow.ConclusionsAn algorithm was developed that analyzes regional and circumferential outflow patterns. This algorithm found flow patterns that changed over time and differ in whole eyes and anterior segment cultures.

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“…Presumably, another venous drainage via the posterior ciliary vein may be responsible for preventing elevation of intraocular pressure. Porcine eyes also have venous outflow through the choroid into the vortex veins and posterior ciliary veins [5], and it has been reported that no significant choroidal drainage effects were observed even though the vortex veins were blocked [20]. In contrast to its frequent occurrence in dogs and cats, glaucoma in horses seems to be rare [21].…”

Section: Discussionmentioning

confidence: 99%

Functional Microvascular Anatomy of the Horse Eye: A Scanning Electron Microscopic Study of Corrosion Casts

Ninomiya

Inomata²

2014

OJVM

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Objective: This study presents the microvasculature of the horse iris, ciliary process, retina, and choroid and discusses the functional significance of the vasculature. Procedure: Seven horses were used for this study. The ocular vascular system was injected with methylmethacrylate resin via the carotid artery, and the vascular corrosion casts were observed using a scanning electron microscope. Results: The iridial vessels showed a wavy course. The ciliary process was supplied by 2 arterial routes: the iridial and ciliary arterial circles. The subjects displayed a paurangiotic retina with retinal vessels extending only a short distance around the disc. The retinal arterioles and venules ran in closely related pairs, and the capillaries formed hairpin loops. No central retinal artery was seen in the equine eyes examined. The choriocapillaris in the avascular retina was arranged in honeycomb hexagon lobules and formed a more densely packed network than that in the vascular retina. There were 2 distinct venous drainage systems in the horse choroid: the vortex veins and the posterior ciliary veins. The vortex vein ampulla was flattened and showed a slit-like lumen at the merge site with the ophthalmic vein. The vortex veins demonstrated a marked constriction before leaving the eye. Discussion: The 2 choroidal drainage systems may compensate each other in event of occlusion. The ampulla and the constriction in the vortex veins may act as a valve regulating the blood flow to keep the eye at an optimum size and the intraocular pressure within the normal physiological range.

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Characterization of Uveoscleral Outflow in Enucleated Porcine Eyes Perfused under Constant Pressure

Abstract: The results suggest that choroidal drainage into the vortex veins is insignificant in the absence of blood perfusion. No significant washout effects in porcine eyes were observed.

Cited by 19 publications

References 18 publications

The parameters of the porcine eyeball

The parameters of the porcine eyeball

Regionally Discrete Aqueous Humor Outflow Quantification Using Fluorescein Canalograms

Functional Microvascular Anatomy of the Horse Eye: A Scanning Electron Microscopic Study of Corrosion Casts

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