The effect of hypoxia on intra-ocular, mean arterial, retinal venous and ocular perfusion pressures

Baertschi, Michael; Dayhaw-Barker, Pierrette

doi:10.3233/ch-152025

Cited by 25 publications

(22 citation statements)

References 32 publications

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“…This indicated that the haemorrhages were due to a hypoxia-induced breakdown of the barrier rather than to mechanical ruptures of a retinal vessel [206]. RVP was increased in diabetic retinopathy [316] and in high-mountain disease [244]. RVP was, as expected, increased in eyes with RVO.…”

Section: Retinal Venous Pressurementioning

confidence: 82%

“…Another patient told us that she became unconscious during a balloon ride. PVD subjects have an increased sensitivity to hypoxia, as it occurs due to low air pressure at high altitudes [244]. One NTG patient experienced a sudden onset of a scotoma during skiing, and three patients became unconscious when jumping into the cold water of the sea.…”

Section: The Patients Are Our Teachers: Clinical Symptoms Of Pvdmentioning

confidence: 99%

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The discovery of the Flammer syndrome: a historical and personal perspective

Flammer

Konieczka

2017

EPMA Journal

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This review describes the clinical and basic research that led to the description of Flammer syndrome. It is narrated from a personal perspective. This research was initiated by the observation of an increased long-term fluctuation of visual fields in a subgroup of glaucoma patients. As these patients had strikingly cold hands, peripheral blood flow was tested with a capillary microscopy, and vasospastic syndrome (VS) was diagnosed. Further studies on these patients revealed frequently weakened autoregulation of ocular blood flow and increased flow resistivity in retroocular vessels. Their retinal vessels were more rigid and irregular and responded less to flickering light. Holistic investigation demonstrated low blood pressure, silent myocardial ischaemia, altered beat-to-beat variation, altered gene expression in the lymphocytes, slightly increased plasma endothelin level and increased systemic oxidative stress. This combination of signs and symptoms was better described by the term primary vascular dysregulation (PVD) than by VS. Subsequent studies showed additional symptoms frequently related to PVD, such as low body mass index, cold extremities combined with slightly increased core temperature, prolonged sleep onset time, reduced feelings of thirst, increased sensitivity to smell and also for certain drugs and increased retinal venous pressure. To better characterise this entire syndrome, the term Flammer syndrome (FS) was introduced. Most subjects with FS were healthy. Nevertheless, FS seemed to increase the risk for certain eye diseases, particularly in younger patients. This included normal-tension glaucoma, anterior ischaemic optic neuropathy, retinal vein occlusions, Susac syndrome and central serous chorioretinopathy. Hereditary diseases, such as Leber’s optic neuropathy or retinitis pigmentosa, were also associated with FS, and FS symptoms and sings occurred more frequent in patients with multiple sclerosis or with acute hearing loss. Further research should lead to a more concise definition of FS, a precise diagnosis and tools for recognizing people at risk for associated diseases. This may ultimately lead to more efficient and more personalised treatment.

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Section: Retinal Venous Pressurementioning

confidence: 82%

Section: The Patients Are Our Teachers: Clinical Symptoms Of Pvdmentioning

confidence: 99%

The discovery of the Flammer syndrome: a historical and personal perspective

Flammer

Konieczka

2017

EPMA Journal

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“…In addition, circulating ET-1 diffuses particularly around the ONH as fenestrated capillaries of the choroid enable diffusion bypassing the blood–retina barrier 20. Increased levels of ET-1 also raise retinal venous pressure as has been documented to occur during high-altitude hypoxia 21. This in turn increases the transmural pressure in the capillaries of the ONH and may therefore contribute to the formation of ODE.…”

Section: Discussionmentioning

confidence: 93%

Optic nerve oedema at high altitude occurs independent of acute mountain sickness

et al. 2018

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“…Auch bei dieser venösen Konstriktion spielen lokale Hormone, insbesondere Endothelin, eine entscheidende Rolle [34]. Dies erklärt dann auch: a) warum der Venendruck in großer Höhe ansteigt [35], b) warum bei einem retinalen Venenverschluss auch der Venendruck auf der kontralateralen, klinisch nicht befallenen Seite erhöht ist [36] und c) warum der retinale Venendruck durch Kalziumantagonisten [37] und Endothelinblocker beeinflusst werden kann [38]. Menschen mit FS haben auch häufiger aktivierte retinale Astrozyten [39].…”

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Phänomenologie und klinische Bedeutung des Flammer-Syndroms

Konieczka

2016

Klin Monatsbl Augenheilkd

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The Flammer syndrome (FS) describes the phenotype of people with a predisposition for an altered reaction of the blood vessels to stimuli like coldness, emotional stress or high altitude. Frequent symptoms are: cold hands and/or feet, low blood pressure, prolonged sleep onset time, reduced feeling of thirst, increased sensitivity to odour, pain, vibration and certain drugs. SF subjects are often ambitious and successful but also perfectionistic and sometimes brooding. Frequent signs are: altered gene expression, prolonged blood flow cessation in nailfold capillaroscopy after cold provocation, reduced autoregulation of ocular blood flow, and reduced vasodilation after stimulation with flickering light. Retinal venous pressure is on the average higher and retinal astrocytes are more often activated. FS occurs more often in females than in males, in thin than in obese subjects, in young than in old people, in graduates than in blue collar workers, in subjects with indoor than outdoor jobs. Associated diseases are: normal tension glaucoma, occlusion of ocular vessels, retinitis pigmentosa, multiple sclerosis, tinnitus or even sudden hearing loss.

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The effect of hypoxia on intra-ocular, mean arterial, retinal venous and ocular perfusion pressures

Abstract: As hypoxia increases with higher altitude, arterial oxygen saturation and ocular perfusion pressure decreased, retinal venous pressure increased, intra-ocular pressure remains stable and mean arterial pressure was elevated only at 6000 m.

Cited by 25 publications

References 32 publications

The discovery of the Flammer syndrome: a historical and personal perspective

The discovery of the Flammer syndrome: a historical and personal perspective

Optic nerve oedema at high altitude occurs independent of acute mountain sickness

Phänomenologie und klinische Bedeutung des Flammer-Syndroms

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