nitrox and the loss of sight

[mania]

Unfortunatly I have lost an issue number 2/2003 of quaterly magazine Immersed. Maybe some of you has this issue and can scan and send me the article concerning loss of sight as a result of Nitrox. I'm precisely looking for the information on hyperoxic-induced myopia (HIM) so maybe you know something more about it? Be grateful for any information
Mania

 

[Saturation]

Unfortunatly I have lost an issue number 2/2003 of quaterly magazine Immersed. Maybe some of you has this issue and can scan and send me the article concerning loss of sight as a result of Nitrox. I'm precisely looking for the information on hyperoxic-induced myopia (HIM) so maybe you know something more about it? Be grateful for any information
Mania

Report has centered mostly on rebreathers who sustained pp02 continuously throughout the dive.

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=10353183&dopt=Abstract

There are a no such reports I know for OC except in 02 tolerance studies of breathing sustained high pp02 [1.6 and up] for multiple hours, not an issue in recreational diving.

 

[miguel sanz]

Report has centered mostly on rebreathers who sustained pp02 continuously throughout the dive.

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=10353183&dopt=Abstract

There are a no such reports I know for OC except in 02 tolerance studies of breathing sustained high pp02 [1.6 and up] for multiple hours, not an issue in recreational diving.

in this abstract they report 3 cases of Hyperoxic myopia while diving on 1.3 ppO2, wich is in the range of recreational diving, although it needs a long exposure hard to get in that setting. Is this taken in acount when you calculate you O2 exposure limit? or just pulmonary tox?

 

[Saturation]

in this abstract they report 3 cases of Hyperoxic myopia while diving on 1.3 ppO2, wich is in the range of recreational diving, although it needs a long exposure hard to get in that setting. Is this taken in acount when you calculate you O2 exposure limit? or just pulmonary tox?

Its only been reported in rebreather dives; rebreathers sustain a pp02 of 1.3 for the entire dive, and such dives are multiple hours long.

There are no reports of such changes breathing nitrox from open circuit, in NSL or deco dives.


In open circuit, you only get a maximum pp02 exposure once at the bottom of the planned dive. There is some protective effect from the gradual increase and decrease of pp02 caused by descending and ascending.


Ocular effects are not directly considered when calculating the toxicity of 02. There are both CNS and whole body toxicity effects on the eye over time. Myopia is likely a form of whole body or pulmonary toxicity since it affects the lens rather than the retina [retina being part of the CNS.] There are known changes in the retina caused by excessive 02 exposure, such as reduction in visual fields and these are as manifestations of CNS toxicity. Some effects are very transient and as the pp02 is reduced, the visual fields improve as quickly. Most of the time the changes are so subtle, then can be found only by medical testing, the patient's do not notice any difference.

It takes a week to 10 days after a high pp02 exposure for all known exposure effects to be normalized.

 

[DocVikingo]

There is absolutely no reason for the healthy diver to worry about occular effects from the ppO2s normally experienced during recreational open circuit scuba.

Best regards.

DocVikingo