What is Boxcarring?

This finding may take hours to develop, and the edema is associated with a worse visual prognosis. Over the course of about a month, the inner retina becomes atrophic as the swelling resolves. Examination of the retinal blood vessels shows segmental blood flow, classically described as boxcarring.

What causes Cilioretinal artery occlusion?

The pathogenesis of CLRAO in CRVO is due to transient hemodynamic blockage of the cilioretinal artery caused by a sudden sharp rise in intraluminal pressure in the retinal capillary bed (due to CRVO) above the level of that in the cilioretinal artery.

How common is a Cilioretinal artery?

Anatomical variants include cilioretinal branches from the short posterior ciliary artery, giving additional supply to part of the macular retina. A cilioretinal artery occurs in approximately 14% of the population.

What is a hollenhorst plaque?

Hollenhorst plaques (Figure 1) refer to yellow, orange refractile cholesterol emboli which occur at retinal arteriole bifurcations arising from carotid or aortic arch atheromatous disease.

What is choroidal vasculature?

The choroid is a vascular bed that supplies nutrients and oxygen to the RPE and outer nuclear layer of the retina. It consists of larger vessels and a highly fenestrated capillary bed known as the choriocapillaris.

Is retinal vein occlusion curable?

There’s no cure for retinal vein occlusion. Your doctor can’t unblock the retinal veins. What they can do is treat any complications and protect your vision.

What causes a hollenhorst plaque?

It is caused by an embolus lodged within the retinal vessel that originated from an atheromatous plaque in a more proximal (upstream) vessel, usually the internal carotid artery. It is often an indication of a previous ischemic episode in the eye and is a sign of severe atherosclerosis.

What is the anatomy of the cilioretinal arteries?

The cilioretinal arteries belong to the posterior ciliary artery system. They usually arise from the peripapillary choroid or directly from one of the short posterior ciliary arteries. The existence of the cilioretinal arteries is a congenital anomaly rather than one acquired due to some disease, inflammatory, or other morbid process.

How do neurons collateralize?

As remarked above, neurons that collateralize do so in a non-stereotyped pattern. Within a designated projection (defined by the origin), neurons send branches to a diversified subset of target areas (“ in all combinations ”).

Can a single neuron have multiple myelinated and unmyelinated collaterals?

Even within the system of intrinsic connections, not only are there differences in number of collaterals and number of synaptic boutons, but a single neuron can have a mix of myelinated and unmyelinated collaterals (cat visual cortex: Martin et al., 2014; Koestinger et al., 2017 ).

How many boutons are there in intrinsic collateralization?

The intrinsic collateralization is exceptionally extensive, measured as 8.0 mm from the soma, on the basis of subtotal reconstructions, and having at least 800–1,370 boutons (Figure 1 ).