Talk:Central retinal artery

Does the Central Retinal Artery have a visible pulse on Fundoscopy?
Ok. So I went to my optometrist the other day and as he was looking in my eye he made a casual comment that he could see the vein in my retina pulsing. Not being able to keep my mouth shut I stated that I was under the impression that arteries should be pulsing, not veins. I told him that I believe him but that I didn’t understand how that could be. He showed me a fundoscopic image of my eye and pointed to where he routinely sees a pulse—we both agreed that it was the central retinal vein. I hypothesized that this pulse was due to its proximity to the artery but neither one of us had a truly satisfying answer. Here’s what I found so far: Bates’ Guide to Physical Examination and History Taking says that venous pulsation may be visible. Swartz’s Textbook of Physical Diagnosis says that the central retinal vein may show “spontaneous pulsation” in 85% of patients. The 39th edition of Gray’s Anatomy is woefully deficient in its description of the central retinal vein (ambiguously indicating forward flow (?)) but it does say that the central retinal artery generally does not have a visible pulse on opthalmoscopy. Moore and Dalley’ Clinically Oriented Anatomy states nothing of venous pulsation but says that “pulsation of the retinal arteries is usually visible." Ross and Pawlina’s Histology was useless.  Rhoades’ and Tanner’s Medical Physiology was also useless.  Barker, Burton, and Zieve’s Principles of Ambulatory Medicine (fifth edition) and Harrison’s Principles of Internal Medicine (thirteenth edition) also were useless.MorbidAnatomy (talk) 00:36, 17 October 2008 (UTC)

answer: The central retinal vein will show a spontaneous pulsation due to the fact that the veinous pressure is close to the intraocular pressure (which is normally between 10 and 21 mmHg). The arterial pressure at head level being higher (approximately 80mmHg), the central retinal artery will not normally show a pulsation. A pulsating central retinal artery is an emergency because it indicates a drop in the arterial pressure, which will generally be caused by a blockage of the common carotid artery. 15:54, 6 July 2013 (UTC)

The central retinal vein (CRV) pulsations are actually transmitted pulsations from central retinal artery (CRA). The pulsations from central retinal artery are transmitted to relatively thin vein walls through the intraocular fluid. Central retinal vein pulsations are seen in 85-90% of the normal people. It may be absent in 10-15% of normal people. Its absence may also indicate increase in cerebrospinal fluid (CSF) pressure greater than 180-190 mmH20. It is one of the early signs of raised CSF pressure. On the contrary, CRA pulsations is an ominous sign, indicating intraocular pressure (IOP) to be higher than CRA pressure. This is an emergent condition warranting immediate reduction of IOP. — Preceding unsigned comment added by 117.199.133.113 (talk) 02:51, 13 October 2013 (UTC)

Spontaneous retinal venous pulsation is seen as a subtle variation in the calibre of the retinal vein(s) as they cross the optic disc. The physical principles behind the venous pulsations has been the point of much debate. Initial theories suggested that the pulsation occurred because of the rise in intraocular pressure in the eye with the pulse pressure. This article presents an argument that this is not the case. The pulsations are in fact caused by variation in the pressure gradient along the retinal vein as it traverses the lamina cribrosa. The pressure gradient varies because of the difference in the pulse pressure between the intraocular space and the cerebrospinal fluid. The importance of this is that as the intracranial pressure rises the intracranial pulse pressure rises to equal the intraocular pulse pressure and the spontaneous venous pulsations cease. Thus it is shown that cessation of the spontaneous venous pulsation is a sensitive marker of raised intracranial pressure. — Preceding unsigned comment added by 103.245.88.100 (talk) 08:32, 24 September 2018 (UTC)