O2 induced myopia (2nd attempt)

saturation

Long terms effects of diving is well described in the medical literature, but there are controversial aspects

http://www.scuba-doc.com/LTE.htm

CCR diving was theoretically more risky in terms of a myopic shift because the 02 setpoint gives the diver a fixed dose of 02 throughout the dive. In OC, that maximum P02 occurs only at the maximum bottom P02 of backgas.

The shift has always been reported as temporary. However, if one dives almost daily with high P02, the shift may have almost no time to normalize, the effect lasts up to 10 days.

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Safe Diving and Best Wishes,

I.G. Saturation, MD

{ Comments are informational only and not meant to be medical advice applicable to a particular case. Consult your physician when considering information posted here }

Fred Evans

I have been diving since I was 16 and was a commercial diver in the North Sea for over 10 years, latterly saturation. I have been doing some pretty aggressive technical diving for the last 8/9 years, the last 3 on CCR. I didn’t need glasses until I was around 45. I now need +1.75 (unless I am experiencing myopia when I need -2.50).

So I don’t think there is too much inherent risk in diving as such, but mix 50+ and a rebreather and it can get interesting (that gives you almost 20 years to go Padowan).

My early air range commercial diving involved surface O2 deco so I have experience many many hours breathing O2 partial pressures above 2 bar so I doubt that even with the advent of widespread rebreather diving that this will increase the risk.

I think genetics are the issue here.

Regards, Fred

Jason Blackwell

Maybe we are putting too much into this…........I mean it is probably from the shock that our eyes saying “ hey you actually went diving instead of reading about rebreathers and diving on the bloody computer screen again”……only joking .

Seriously, ScubaDadMiami mentioned that Tom M knew of 2 divers who regularly suffered from it……….well I believe I personally know both of them, so Cedric if you would like me to put you in touch with these two please PM me.

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Sutty

I noticed this for the 1st time on returning to the UK after the RebreatherWorld Red Sea trip. Was more short-sighted than usual for a few days only. Suspect I didn't notice it on the trip due to the higher light levels.

Neil

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Hancock

Hi Cedric, I have (had) H.I.M. and it is pretty bad. I first experienced it at the age of 48 or 49 after a trip to the Solomon Is. in 2002. I spent 46 hours or so in the water with a PO2 of about 1.1 over a period of 13 days. After this trip my eyes crashed and went myopic. I stayed within the Hamilton Repex tables. Regardless, my eyes only partially recovered. Prior to this experience I did not need corrective lenses. I've mentored a bit with Howard Hall who has of course experienced similar problems. He (we) think that the O2 exposure has caused the lens in our eyes to become rigid and less focusable. I've become almost hyper-sensitive to O2 exposure now and it does not take too much to have my eyes go very blurry. Howard has developed some good strong theories that it is not the breathed O2 but rather the O2 in the mask. It seems that contact lenses may help protect the eyes from the O2?!
Meanwhile I've developed cataracts at a relatively young age due to the O2 and had lens implants this month. I'm very hopeful that this will take care of my eye problems. I could elaborate extensively on this subject if you are interested. I also wrote an article about this in Imersed-Summer 03.
Dave (Meg10)

apitkin

This seems to be the case for chamber-associated hyperoxic myopia, where patients using hoods seem to be more prone to the problem than those using an oronasal BIBS mask. Not sure if contact lenses would help, but it's a great idea for a neat piece of research. Taking a breath of diluent before clearing your mask probably won't help much, as it won't dilute the gas in your lungs much.

We ran a hyperbaric clinical trial which was blinded (!) by supplying different gas mixes to the treatment and control groups. Unfortunately the patients receiving the active treatment (oxygen) were usually able to work out that they were getting it by the change in their refractive index. Several were able (temporarily) to do without glasses they'd used for years.

Andy

Sutty

Not sure this has to be the case as if you only use the first part of your exhale for clearing it will be mainly dead-space gas which should be pretty much undiluted diluent - worth a try at least!

Neil

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Gene_Hobbs

There is a nice write up here on vision effects after multiple days of 1.35 pO2 diving. The abstract focuses on pulmonary effects but the variation of dive days and total number of days with vision effects described here was interesting. (page 17)

Repeated Six-Hour Dives 1.35 ATM Oxygen Partial Pressure.
Shykoff NEDU report 2005-20
RRR ID: 3492

Another case report:
Hyperoxic myopia in a closed-circuit mixed-gas scuba diver.
Butler et. al. Undersea and Hyperbaric Medicine 1999
RRR ID: 2312

A good portion of those references are available.

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saturation

I have had 02 induced myopia on open circuit at least 3 times doing 4 hours runtime dives for 3 hour bottom times at Devils Cave System. It persists for about 1 week, and after the 1st episode, did a visual acuity check at least twice before and after a dive trip. The shift is from 20/20 corrected, to 20/40 corrected.

I've been able to reduce the shift by insuring my mask doesn't contain 02 [ suspecting that as a worsening factor] as I often exhale through my nose to clear my sinuses, which gets very stuffy after long 02. I now do the nose clearing during my backgas break.

I have put the details together for a UHMS abstract but haven't had the time to formally write it, and this is just a case study of me only.

I think the reason it was easy to detect was that I'm on the verge of needing new glasses, and compensate for it by a lot of ciliary muscle action, I often get eye fatigue by day's end. After the shift caused by 02, whatever its etiology truly is, my muscles can no longer compensate and the myopia ensues.

__________________
Safe Diving and Best Wishes,

I.G. Saturation, MD

{ Comments are informational only and not meant to be medical advice applicable to a particular case. Consult your physician when considering information posted here }

silent running

Hello everybody, I don't wear glasses and I do almost all of my diving on multi day trips for as long as a month. On the longer trips, I give my body a few days off around the 2 week mark. I dive 2-4 times a year, so there are long breaks btw these long exposures. Thus far I've not noticed any O2 myopia.

However, I recently returned from another multi day CCR dive trip-53.5 hrs over 11 days-and while I've not noticed any myopia, I did seem to have a dip in my night vision, which seems to have returned to normal after about 2 weeks. I am 42 and like most people, I've had a slight decline in my near vision over the last few years, so it's possible I'm imagining it. Anybody else notice a decrease in night vision after long O2 exposures? Anybody have an idea why my night vision would be affected, but not my near sight?

Thanks, -Andy