O2 induced myopia (2nd attempt)

abowie · 14th January 2006, 23:25

Gentlemen this is most interesting.

While I admit to having no experience whatsoever in this regard, as per my previous reply to Cedric's initial post in August 2005 this is supposed to be pretty uncommon and require a LOT of O2 exposure.

Is there any possibility that one or more of you would be prepared to have your eyesight checked before and after a dive trip to get an objective measure of the changes?

If this is occurring as commonly as this thread suggests it might be worth writing it up in a journal somewhere.

http://www.rebreatherworld.com/dive-...yopia.html#top

***ScubaDadMiami*** · 16th January 2006, 01:34

Second hand is the best I can offer here. I am in the middle of training right now. Today, my instructor told me that he personally knows people who have experienced myopia caused by high O2 exposures over several days. Additionally, he told me that once one has the condition, it is easier to cause it again in the future (for perhaps the rest of the subject's life).

Fred Evans · 16th January 2006, 07:58

The degree of change is sufficiently constant that I have found that the same pair of corrective lenses work each time, but as I mentioned before my dive trips tend to have roughly the same level of exposure so it doesn’t tell us too much.

My glasses are +1.75 normally and the others are -2.50 (I will have to find the slip to confirm) so you can see that the impact is significant.

What I will attempt to do this year is record the uptds on a daily basis and test my eyes each evening when on multi day trips. From an anecdotal perspective it does seem to be all or nothing in terms of impact, and if I remember Kevin’s experiences correctly he did not have much luck simply reducing the SP a couple of points.

I am diving with Kevin this weekend (blind leading the blind so to speak) so will talk it over and see if we can provide any more meaningful insights between us.

We have some deep dives later this year which should also enable me to determine if the impact is the same for a single very high loading dive vs multi day accumulation.

Regards, Fred

**Simon TW** · 16th January 2006, 10:26

Quote: (Originally Posted by ScubaDadMiami)

Additionally, he told me that once one has the condition, it is easier to cause it again in the future (for perhaps the rest of the subject's life).

Not wishing to off at a tangent, can anyone give more information on this.

I'd never experienced it before but I had it really bad after my Chamber dives.

***ScubaDadMiami*** · 17th January 2006, 03:11

Quote: (Originally Posted by Simon TW)

Not wishing to off at a tangent, can anyone give more information on this.

I'd never experienced it before but I had it really bad after my Chamber dives.

I will try to remember to ask for some specifics about it during the next class. I hope I remember. There's an awful lot of remembering I have to do during my instruction!

saturation · 28th March 2006, 20:09

Increasingly, there are more reports of myopia on exposure to hyperoxia via any means:

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum

decompression_man · 29th March 2006, 12:31

Hi Cedric,

Yes I experienced it after 6 days diving in the Red Sea the beginning of this month, having done 20hrs 2mins according to the Evo. Used 1.3 setpoint at the bottom for pretty much the whole time.

Just got my eyes examined and new contact lenses prior to the trip, so I knew everything was ok. I use my contact lenses for diving and I wear my "long sight" prescription of -3.25 in my left predoninent eye and my reading prescription of -1.75 in my left for reading my instruments.

At the end of the week I could actually read with my -3.25 "long sight" contact lens prescription in my left eye and obviously distant objects were blurred. I am 48yrs of age and well within the age it is expected, although from what I have read, it should happen after a far longer exposure period. I have experienced it in the past after a liveaboard trip, so knew what to expect.

After two weeks all is back to normal, when I'm sober.

Leon

saturation · 29th March 2006, 13:14

To add my anecodote. We are doing dives with over 1 hour deco. In nearly all instances I get a myopic shift, but its very subtle. This is on open circuit. Once it was very bad, down to 20/50. However, since I stopped exhaling 02 into my mask, the shift hasn't been as bad.

The difference can be very subtle, but while I notice it subjectively, it can be tested with some objectivity using a Snellen chart.

There are charts calibrated for Internet users.

May I suggest you folks check your eyes before and after a dive holiday and get a quantitative reading of the change? I think this shift is very common, more common that is listed in the medical literature.

http://www.mdsupport.org/snellen.html

Its important to make sure the letter size is correct and the subject is standing the proper distance away from the computer monitor, and test one eye at a time using your everyday lenses.

The chart is in metric, but follow the instructions to convert to US units if needed.

cedricverdier · 29th March 2006, 13:34

Quote: (Originally Posted by saturation)

To add my anecodote. We are doing dives with over 1 hour deco. In nearly all instances I get a myopic shift, but its very subtle. This is on open circuit. Once it was very bad, down to 20/50. However, since I stopped exhaling 02 into my mask, the shift hasn't been as bad.

The difference can be very subtle, but while I notice it subjectively, it can be tested with some objectivity using a Snellen chart.

There are charts calibrated for Internet users.

May I suggest you folks check your eyes before and after a dive holiday and get a quantitative reading of the change? I think this shift is very common, more common that is listed in the medical literature.

http://www.mdsupport.org/snellen.html

Its important to make sure the letter size is correct and the subject is standing the proper distance away from the computer monitor, and test one eye at a time using your everyday lenses.

The chart is in metric, but follow the instructions to convert to US units if needed.

very interesting! thanks for the link.

I have something new to do before and after the dives now...

Cheers

Padowan · 29th March 2006, 13:58

I'm interested in the longer term effects of diving, both OC and CCR. I used to have 20:20 vision before I started diving, recreational depths at first, then deeper, longer then onto a CCR, deep and long. About 18 months ago I got my eyes tested and needed glasses (I have a -1.00 prescription in both eyes now) they're not very strong ones, but the deterioration in my ability to see things in the distance is noticable, and I think it's still changing, but I've not had them tested recently.

I've not noticed anything while diving, and don't use any sort of prescription mask, but have often wondered if there may be a link between the slight, gradual deterioration of my sight, and the amount of diving that I've been doing.

I'm 31 now, and started diving just over 6 years, so it might be just age creeping up on me....

14th January 2006, 23:25	#11 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 573	Re: O2 induced myopia (2nd attempt) Gentlemen this is most interesting. While I admit to having no experience whatsoever in this regard, as per my previous reply to Cedric's initial post in August 2005 this is supposed to be pretty uncommon and require a LOT of O2 exposure. Is there any possibility that one or more of you would be prepared to have your eyesight checked before and after a dive trip to get an objective measure of the changes? If this is occurring as commonly as this thread suggests it might be worth writing it up in a journal somewhere. http://www.rebreatherworld.com/dive-...yopia.html#top __________________ Andrew Bowie Rebreather-friendly Buddy
(Offline)

16th January 2006, 01:34	#12 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,068	Re: O2 induced myopia (2nd attempt) Second hand is the best I can offer here. I am in the middle of training right now. Today, my instructor told me that he personally knows people who have experienced myopia caused by high O2 exposures over several days. Additionally, he told me that once one has the condition, it is easier to cause it again in the future (for perhaps the rest of the subject's life). __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
(Offline)

16th January 2006, 07:58	#13 (permalink)
Fred Evans Old Bull Current Rebreather/s: Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: Indonesia, Jakarta Posts: 51	Re: O2 induced myopia (2nd attempt) The degree of change is sufficiently constant that I have found that the same pair of corrective lenses work each time, but as I mentioned before my dive trips tend to have roughly the same level of exposure so it doesn’t tell us too much. My glasses are +1.75 normally and the others are -2.50 (I will have to find the slip to confirm) so you can see that the impact is significant. What I will attempt to do this year is record the uptds on a daily basis and test my eyes each evening when on multi day trips. From an anecdotal perspective it does seem to be all or nothing in terms of impact, and if I remember Kevin’s experiences correctly he did not have much luck simply reducing the SP a couple of points. I am diving with Kevin this weekend (blind leading the blind so to speak) so will talk it over and see if we can provide any more meaningful insights between us. We have some deep dives later this year which should also enable me to determine if the impact is the same for a single very high loading dive vs multi day accumulation. Regards, Fred
(Offline)

16th January 2006, 10:26	#14 (permalink)
Simon TW Martini Diver Current Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Other Rebreather/s: Join Date: May 2005 Location: Hurghada (Egypt) and Lancaster (England) Posts: 157	Re: O2 induced myopia (2nd attempt) Quote: (Originally Posted by ScubaDadMiami) Additionally, he told me that once one has the condition, it is easier to cause it again in the future (for perhaps the rest of the subject's life). Not wishing to off at a tangent, can anyone give more information on this. I'd never experienced it before but I had it really bad after my Chamber dives.
(Online)

17th January 2006, 03:11	#15 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,068	Re: O2 induced myopia (2nd attempt) Quote: (Originally Posted by Simon TW) Not wishing to off at a tangent, can anyone give more information on this. I'd never experienced it before but I had it really bad after my Chamber dives. I will try to remember to ask for some specifics about it during the next class. I hope I remember. There's an awful lot of remembering I have to do during my instruction! __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
(Offline)

28th March 2006, 20:09	#16 (permalink)
saturation New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2005 Location: Philadelphia, PA, USA Posts: 53	Re: O2 induced myopia (2nd attempt) Increasingly, there are more reports of myopia on exposure to hyperoxia via any means: http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum __________________ 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 }
(Offline)

29th March 2006, 12:31	#17 (permalink)
decompression_man New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Oct 2005 Location: Swansea, South Wales Posts: 25	Re: O2 induced myopia (2nd attempt) Hi Cedric, Yes I experienced it after 6 days diving in the Red Sea the beginning of this month, having done 20hrs 2mins according to the Evo. Used 1.3 setpoint at the bottom for pretty much the whole time. Just got my eyes examined and new contact lenses prior to the trip, so I knew everything was ok. I use my contact lenses for diving and I wear my "long sight" prescription of -3.25 in my left predoninent eye and my reading prescription of -1.75 in my left for reading my instruments. At the end of the week I could actually read with my -3.25 "long sight" contact lens prescription in my left eye and obviously distant objects were blurred. I am 48yrs of age and well within the age it is expected, although from what I have read, it should happen after a far longer exposure period. I have experienced it in the past after a liveaboard trip, so knew what to expect. After two weeks all is back to normal, when I'm sober. Leon
(Offline)

29th March 2006, 13:14	#18 (permalink)
saturation New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2005 Location: Philadelphia, PA, USA Posts: 53	Re: O2 induced myopia (2nd attempt) To add my anecodote. We are doing dives with over 1 hour deco. In nearly all instances I get a myopic shift, but its very subtle. This is on open circuit. Once it was very bad, down to 20/50. However, since I stopped exhaling 02 into my mask, the shift hasn't been as bad. The difference can be very subtle, but while I notice it subjectively, it can be tested with some objectivity using a Snellen chart. There are charts calibrated for Internet users. May I suggest you folks check your eyes before and after a dive holiday and get a quantitative reading of the change? I think this shift is very common, more common that is listed in the medical literature. http://www.mdsupport.org/snellen.html Its important to make sure the letter size is correct and the subject is standing the proper distance away from the computer monitor, and test one eye at a time using your everyday lenses. The chart is in metric, but follow the instructions to convert to US units if needed. __________________ 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 }
(Offline)

29th March 2006, 13:34	#19 (permalink)
cedricverdier S21 M.I.B. Current Rebreather/s: Evolution Megalodon Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Worldwide! Posts: 494	Re: O2 induced myopia (2nd attempt) Quote: (Originally Posted by saturation) To add my anecodote. We are doing dives with over 1 hour deco. In nearly all instances I get a myopic shift, but its very subtle. This is on open circuit. Once it was very bad, down to 20/50. However, since I stopped exhaling 02 into my mask, the shift hasn't been as bad. The difference can be very subtle, but while I notice it subjectively, it can be tested with some objectivity using a Snellen chart. There are charts calibrated for Internet users. May I suggest you folks check your eyes before and after a dive holiday and get a quantitative reading of the change? I think this shift is very common, more common that is listed in the medical literature. http://www.mdsupport.org/snellen.html Its important to make sure the letter size is correct and the subject is standing the proper distance away from the computer monitor, and test one eye at a time using your everyday lenses. The chart is in metric, but follow the instructions to convert to US units if needed. very interesting! thanks for the link. I have something new to do before and after the dives now... Cheers __________________ Cedric Verdier PADI Course Director, ANDI-IANTD-PSAI-TDI-DSAT-DAN-NAUI-CMAS Instructor Trainer Trimix (CCR and OC) and Cave Diving Instructor Trainer www.CedricVerdier.com DIRrebreather member
(Offline)

29th March 2006, 13:58	#20 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	Re: O2 induced myopia (2nd attempt) I'm interested in the longer term effects of diving, both OC and CCR. I used to have 20:20 vision before I started diving, recreational depths at first, then deeper, longer then onto a CCR, deep and long. About 18 months ago I got my eyes tested and needed glasses (I have a -1.00 prescription in both eyes now) they're not very strong ones, but the deterioration in my ability to see things in the distance is noticable, and I think it's still changing, but I've not had them tested recently. I've not noticed anything while diving, and don't use any sort of prescription mask, but have often wondered if there may be a link between the slight, gradual deterioration of my sight, and the amount of diving that I've been doing. I'm 31 now, and started diving just over 6 years, so it might be just age creeping up on me.... __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode