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I read with interest the article “Spontaneous retinal venous pulsation: aetiology and significance” by Jacks and Miller.1 Their explanation for these pulsations is essentially no different from that put forward by Levine in 1998.2 They then go on to discuss the clinical importance of spontaneous retinal venous pulsations (SVPs). They refer to the finding of Levin that the presence of SVPs is an indication of an intracranial pressure below 190 mm H20.3 However, they conclude without justification that “presence of SVPs allows the examiner to conclude that the patient does not have optic disc swelling...”.
We cannot conclude that because an individual has SVPs there is no true disc swelling. Shortly after their article was published, a 53 year old man was referred to us by his optometrist with “raised discs”. On examination, he was found to have markedly elevated optic discs, with an SVP in the left eye. After a normal head CT scan, the patient had a lumbar puncture with an opening pressure of 400 mm H20, leading to a diagnosis of papilloedema secondary to idiopathic intracranial hypertension. If we had concluded that the discs were not in fact truly swollen (pseudopapilloedema), we would have had no justification for performing these investigations which lead to treatment, and the patient would have been much more likely to suffer irreversible visual loss. Persons with disc swelling due to ischaemic or inflammatory causes may also have SVPs in the affected eye, although less often than in unaffected eyes.4
The presence of SVPs can be used to provide an upper limit for a patient’s CSF pressure, but says nothing about whether or not the disc is swollen. The finding of an SVP can indicate whether papilloedema is likely, but not whether it is actually present, as illustrated by our case. Perhaps the best message on this topic derives from an authoritative neuro-ophthalmic text: “The observation of spontaneous venous pulsations indicates only that ICP is below 200 mm of water at that time, not that the patient does not have papilloedema.”5
Jacks and Miller have provided a review based mostly on two original articles, one of which quite adequately described the clinical significance of SVPs. They have then in our opinion drawn unfounded, incorrect, and inevitably harmful conclusions.
We thank McKee and Ahad for their letter in which they question our statement that “the presence of spontaneous venous pulsations (SVPs) allows the examiner to conclude that the patient does not have optic disc swelling”. Although we believe this statement to be generally true, and agree with McCulley et al1 that most discs with optic disc swelling do not show SVPs, persons with mild papilloedema, particularly individuals with pseudotumour cerebri, have significant fluctuations in intracranial pressure (ICP). Such people may indeed show SVPs during the period throughout which their ICP is normal. Thus, the decision as to whether or not an elevated disc is truly swollen should never be made entirely on the presence or absence of SVPs, but on the entire clinical picture.
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