bubbles in conjunctival sac

[DivingDoc]

I read an article in a recent issue of Rodale's -- the same issue that had the big review on fins. It reported on a study that was done where they found that divers who had DCS symptoms were likely to have more bubbles in the fluid in their lower conjuctival sac. Asymptomatic divers had only 3-5 bubbles, but those with possible DCS had 20-30 bubbles. They were thinking that this test might be an easy one to do as part of an exam looking for symptoms of DCS. Of course, the exam they did was done with a slit lamp -- hardly a piece of equipment that would be found on a boat.

What does Dr. Deco think about this???

 

[Diver0001]

DivingDoc once bubbled...
I read an article in a recent issue of Rodale's -- the same issue that had the big review on fins. It reported on a study that was done where they found that divers who had DCS symptoms were likely to have more bubbles in the fluid in their lower conjuctival sac. Asymptomatic divers had only 3-5 bubbles, but those with possible DCS had 20-30 bubbles. They were thinking that this test might be an easy one to do as part of an exam looking for symptoms of DCS. Of course, the exam they did was done with a slit lamp -- hardly a piece of equipment that would be found on a boat.

What does Dr. Deco think about this???

On the assumption that a ... what was it .... "lower conjuctival sac" is an eyelid, then yes. I've heard of this too.

I took the following article from divernet in march of 2002.

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NEW TEST FOR DECOMPRESSION ILLNESS

Doctors at the University of New South Wales Department of diving and Hyperbaric Medicine claim to have discovered a simple method of identifying decompression illness.

Research carried out on scuba divers revealed that after every dive between one and three bubbles are visible in the fluid that lubricates the eyeball. These are visible in the tear film in the lower eyelid. In case of divers with decompression illness, between 20 and 30 bubbles can be observed.

"We hope that a remote doctor, suspicious that a patient may have the bends, will be able to do a simple, inexpensive examination of the patient's tear film. Based on the number of air bubbles, they will then be able to make a decision on whether the patient needs to be flown out for further treatment," said Dr Bennett, the report's author.

Monday 4 March, 2002

==============

 

[Dr Deco]

Dear DivingDoc:

This is a reply from a FORUM of last year. I have used parts of it to save time.

Bubbles In the Eye

The study to which you are referring in Rodale’s involves as study by some physicians from Australia. [The Dr Bennett mentioned is not the same as the one at DAN.]

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. Becasue the bubbles are fairly large, they could probably be seen with a strong hand lens; the minimum magnification of a biomicroscope is generally given as 6X,

How Does It Work?

This is my assessment based on what has been written. [I have already communicated this to the Croatian authors.] The surface tension of the tear film (lachrymal fluid is about 40 dynes/cm) is quite a bit lower than that of blood (serum; serface tension = 60 dynes/cm). Thus lower gas tensions would be required to cause A MICRONUCLEUS TO GROW (the Laplace radius could be larger) 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:

 

[yogevdan]

Dear DivingDoc:

This is a reply from a FORUM of last year. I have used parts of it to save time.

Bubbles In the Eye

The study to which you are referring in Rodale’s involves as study by some physicians from Australia. [The Dr Bennett mentioned is not the same as the one at DAN.]

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. Becasue the bubbles are fairly large, they could probably be seen with a strong hand lens; the minimum magnification of a biomicroscope is generally given as 6X,

How Does It Work?

This is my assessment based on what has been written. [I have already communicated this to the Croatian authors.] The surface tension of the tear film (lachrymal fluid is about 40 dynes/cm) is quite a bit lower than that of blood (serum; serface tension = 60 dynes/cm). Thus lower gas tensions would be required to cause A MICRONUCLEUS TO GROW (the Laplace radius could be larger) 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:

hello dr deco,

i am new in the field and currently gathering information about decompression sickness and advances in diagnosis of DCS, what would you reccomend as a good start point for understanding the decompression syndrome,diagnosis and research?
thanks,
danny.

 

[Dr Deco]

Hello yogevdan:

Bennett and Elliott book

The fifth edition of the Bennett and Elliott (Physiology and Medicine of Diving) book is the best complete source for DCS information. It is not an elementary text, however. It is also expensive but can probably be obtained from a local library, though they might need to send outside their system for it (interlibrary loan).


One can also continue to check with this FORUM thought the questions asked are somewhat random.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :1book:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[yogevdan]

Hello yogevdan:

Bennett and Elliott book

The fifth edition of the Bennett and Elliott (Physiology and Medicine of Diving) book is the best complete source for DCS information. It is not an elementary text, however. It is also expensive but can probably be obtained from a local library, though they might need to send outside their system for it (interlibrary loan).


One can also continue to check with this FORUM thought the questions asked are somewhat random.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :1book:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

got the book! thanks. (it is just what i needed)