Sign of DCS?

[undah20]

Dr. Deco, or anyone who can help with this?

I'm not verse in medical information or terms, so please have patience: In reading an article from Rodale's quite a time ago, it mentioned there was a study underway looking for signs of possible DCS from development of increasingly large numbers of bubbles in the fluid of the eye sockets.

The abreviated article told that there are normally a number of measurable bubbles present within the fluid the surounds the eyeball within the eye socket. Research on a recently surfaced diver(s) who upon examination was found to have many more times the "normal" amount of bubble quantities, and a coorelation was being attempted for signs of DCS. It was hoped that in the future, someone suspected of possible DCS/DCS may have a simple eye exam performed, and possibly the chances of proper recognition and treatment could be more assured.

The article lead to no further research points for more information. Does anyone know if this is still ongoing, became a reality, had value, or could lead me on where to research more into the results of the findings? Any help would be appreciated!

Thanks!

UndaH20

 

[Dr Deco]

Dear undaH2O:

Bubbles In the Eye

The study to which you are referring in Rodale’s involves as study by some physicians from Australia. This study was also report several years ago by diving scientists from Simon Fraser University in Canada, now living in Croatia. Another Canadian reported bubbles beneath a contact lens. The finding was that gas bubbles form in the tears of the eye and can be seen with a magnifying device (to be exact, a slit lamp). The number of bubbles has not yet been correlated with the severity of the dive. Therefore it is not clear that this test can be utilized to assist in the diagnosis of DCS.

How Does It Work?

This is my assessment based on what has been written. [I have already communicated this to the Croatian authors so there would be no surprise there.] The surface tension of the tear film (lachrymal fluid) is quite a bit lower than that of blood (serum). Thus lower gas tensions would be required to cause A MICRONUCLEUS TO GROW under the eyelid than in the blood or tissues. The nuclei form from the blinking of the eyelid by a process referred to as hydrodynamic cavitation.

Since bubble formation is easier in the tear film that tissues, seeing these bubbles would serve as a type of early warning system. This is not unlike the Doppler devices currently in use.

What Is The Problem?

The general difficulty with Doppler devices is that they detect decompression gas bubbles in many dive situations. This is true even in the complete absence of clinical DCS. This would probably be true also of tear-film bubbles.

One problem with Doppler bubbles is that they are also short lived. One hour after a diver has DCS, someone listening for Doppler bubbles will probably not hear them with the Doppler ultrasound flow meter. Thus its diagnostic value is questionable. The films might be better in this regard. It would reduce the number of false negatives of Doppler one hour post DCS.

What Is Next?

Things similar to this require time to get the proper validation. It probably would require the decompression of divers in a chamber beyond the no – deco limits to increase the “dose” of nitrogen. We will keep an eye out for this (pun intended).

Dr Deco :doctor:

[on vacation this week]:mean:

 

[MonkSeal]

Dr Deco,

Can you post a link where a work of these Croatian scientists can be found ?

Regards
MonkSeal

 

[madmole]

Annecdotal I know, But I was the DO of a large (>300 member) scuba club in the late 70's, early 80's when hard contact lenses first appeared

We had numerous problems at the time, due to blurred vision while surfacing and just after surfacing, we put this down to degassing under the virtually non permable lenses and indeed the BSAC even sent out notices to this effect

Of course as the contacts improved and become more permeable this phenomena went away, but it definately leads credence to the tears offgassing theory

NO DIVERS WERE BENT OR HURT IN THE MAKING OF THIS MESSAGE!

 

[rmediver2002]

No link but here is the most recent reference I know of on the subject...

Bennett M, Doolette D, Heffernan N. Ocular tear film bubble counts after recreational compressed air diving. Undersea and Hyperbaric Medicine 2001; 28(1):1-7


Jeff Lane

 

[MonkSeal]

I'm from Croatia, so I think maybe I can get in touch with the scientists Dr Deco mentioned and to check if they published something here in Croatian.

MonkSeal

 

[Dr Deco]

Dear MonkSeal:

Igor

When Dr Igor Mekjavic wrote the paper referenced below, he was at this address: Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Slovenia

Abstract

Mekjavic IB, Campbell DG, Jaki P, Dovsak PA. Ocular bubble formation as a method of assessing decompression stress. Undersea Hyperb Med 1998 Winter;25(4):201-10

Department of Sports & Exercise Science, Faculty of Science, University of Portsmouth, United Kingdom.

Tear film bubble formation and ultrasound reflectivity of the lens-vitreous humor compartments were monitored following simulated dives in a hyperbaric chamber. the sensitivity of these methods in determining decompression stress was compared with the results of precordial Doppler ultrasound. In addition, the
utility of these diagnostic techniques in testing decompression dive profiles was evaluated. Eleven divers completed two series of chamber dives according to the decompression schedule of the Professional Association of Diving Instructors. The first dive series comprised dives to 70 feet of seawater (fsw) for 15, 29, and 40 min. The second series comprised maximum duration no-stop decompression dives to 40 fsw for 140 min, 70 fsw for 40 min, 90 fsw for 25 min, and 120 fsw for 13 min. Before and immediately after each dive, the following measurements were obtained from each subject: eye surface tear film bubble counts with a slit-lamp microscope, lens and vitreous humor reflectivity using A- and B-mode ophthalmic ultrasonic scan, and precordial Doppler ultrasonic detection of venous gas bubbles. Tear film bubble assessment and ocular scanning ultrasound were observed to be more sensitive in detecting decompression stress than the conventional Doppler ultrasonic surveillance of the precordial region. In contrast to precordial Doppler ultrasonic surveillance, which failed to detect any significant changes in circulating bubbles, tear film bubble formation displayed a dose-response relationship with increasing duration of the 70-fsw dives. Reflectivity changes of the lens-vitreous humor interface were not significant until the no-stop decompression limit was reached. In addition, for each of the no-stop decompression limit dives, increases in the average tear film bubble formation and lens-vitreous humor interface reflectivity were similar. Ocular bubble observations may provide a practical and objective ocular bubble index for analyzing existing decompression schedules and predicting individual susceptibility to decompression sickness.

E-mail

The last e-mail address I have is :

igor.mekjavic@ijs.si If you reach him, please tell him “hello” for me.

Dr Deco :doctor:

[On vacation this week] :mean:

 

[MonkSeal]

Thanks, Dr Deco.

MonkSeal