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Eye pressures

Reply from: Don W
Date: 27 Apr 2008, 05:34
Eye pressures

Went to an eye talk couple days ago. The following (unresolved) question
came up. When eye pressures are up (say in the posterior part of the eye)
it affects the optic nerve. But pressures are measure in the front of the
eye. The front chamber (anterior) is separated from the back chamber by the
lens, etc. In the front chamber, a liquid solution, in the rear a vitreous
gel. So when the doctor measures the pressure in the front, what gives him
some indication that these two chambers track, that is, their pressures are
about the same?

Don W.





Reply from: Salmon Egg
Date: 28 Apr 2008, 02:57
Re: Eye pressures

In article <wvSQj.11450$V14.4336@nlpi070.nbdc.sbc . com >,
"Don W" <dwilgus@prodigy . net > wrote:

> Went to an eye talk couple days ago. The following (unresolved) question
> came up. When eye pressures are up (say in the posterior part of the eye)
> it affects the optic nerve. But pressures are measure in the front of the
> eye. The front chamber (anterior) is separated from the back chamber by the
> lens, etc. In the front chamber, a liquid solution, in the rear a vitreous
> gel. So when the doctor measures the pressure in the front, what gives him
> some indication that these two chambers track, that is, their pressures are
> about the same?
>
> Don W.

Two words: Pascal's Law.

Bill

Reply from: Dave Bell
Date: 28 Apr 2008, 04:04
Re: Eye pressures

Salmon Egg wrote:
> In article <wvSQj.11450$V14.4336@nlpi070.nbdc.sbc . com >,
> "Don W" <dwilgus@prodigy . net > wrote:
>
>> Went to an eye talk couple days ago. The following (unresolved) question
>> came up. When eye pressures are up (say in the posterior part of the eye)
>> it affects the optic nerve. But pressures are measure in the front of the
>> eye. The front chamber (anterior) is separated from the back chamber by the
>> lens, etc. In the front chamber, a liquid solution, in the rear a vitreous
>> gel. So when the doctor measures the pressure in the front, what gives him
>> some indication that these two chambers track, that is, their pressures are
>> about the same?
>>
>> Don W.
>
> Two words: Pascal's Law.
>
> Bill
That and the fact that the pars plana (lens, etc.) is not a rigid structure.

Dave

Reply from: Salmon Egg
Date: 28 Apr 2008, 08:19
Re: Eye pressures

In article <cjaRj.23220$%41.18932@nlpi064.nbdc.sbc . com >,
Dave Bell <dbell@TheSPAMFREEBells . net > wrote:

> That and the fact that the pars plana (lens, etc.) is not a rigid structure.

From what I understand, the most likely source of error is a thick
cornea that does not act like a baloon. At least with the pneumatic
measurement technique.

Reply from: Dr Judy
Date: 28 Apr 2008, 17:53
Re: Eye pressures

On Apr 26, 11:34 pm, "Don W" <dwil...@prodigy . net > wrote:
>   Went to an eye talk couple days ago.  The following (unresolved) que=
stion
> came up.  When eye pressures are up (say in the posterior part of the ey=
e)
> it affects the optic nerve.  But pressures are measure in the front of t=
he
> eye.  The front chamber (anterior) is separated from the back chamber by=
the
> lens, etc.  In the front chamber, a liquid  solution, in the rear a vi=
treous
> gel.  So when the doctor measures the pressure in the front, what gives =
him
> some indication that these two chambers track, that is, their pressures ar=
e
> about the same?
>
> Don W.

The fluid in the two chambers is connected. Aqueous humour (front
liquid) is produced behind the lens and flows through the pupil to the
front.

Dr Judy




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