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Re desired IOP levels

Question:

To all,     I emailed Ray Bonar last week asking him if he’d run the issue of ideal IOP levels past Dr. Ritch for our edification, and today the following was forwarded to me: "Hi Ray "The 22 mmHg dividing line was a statistical derivation from the 1950s which held sway for a generation.  The definitions are presently in flux. If someone has an IOP of 40 and you lower it to 20, they should do all right.  However, someone who is losing field at IOP 24 will probably not do all right in the long run with lowering to 20.  What we condeptualize now is that an IOP is too high if the patient loses field at that IOP, whatever it is.  For many patients, we are resetting target pressures to around 16, rather than 21.  Obviously, if someone is losing field at 14, other, non-pressure-dependent risk factors, are at play.  However, treating these is still in its infancy. "Robert Rich, MD "Professor and Chief, Glaucoma Service "the New York Eye and Ear Infirmary" etc.

Response:

Obviously, condeptualize was a typo.  Should be conceptualize. Donald Singleton <donal…@sprynet.com> wrote in article <01bccb8c$f16ddbe0$409baec7@default>… – Hide quoted text — Show quoted text -> To all, >     I emailed Ray Bonar last week asking him if he’d run the issue of ideal > IOP levels past Dr. Ritch for our edification, and today the following was > forwarded to me: > "Hi Ray > "The 22 mmHg dividing line was a statistical derivation from the 1950s > which held sway for a generation.  The definitions are presently in flux. > If someone has an IOP of 40 and you lower it to 20, they should do all > right.  However, someone who is losing field at IOP 24 will probably not do > all right in the long run with lowering to 20.  What we condeptualize now > is that an IOP is too high if the patient loses field at that IOP, whatever > it is.  For many patients, we are resetting target pressures to around 16, > rather than 21.  Obviously, if someone is losing field at 14, other, > non-pressure-dependent risk factors, are at play.  However, treating these > is still in its infancy. > "Robert Rich, MD > "Professor and Chief, Glaucoma Service > "the New York Eye and Ear Infirmary" > etc.

Response:

bo…@tiac.net (Ray Bonar) wrote: >Hi Vernon; >Dr. Robert Ritch responds that your basically on the right track. I >have little to argue with. IOP is not the only game in town, however, >at the end of 1997. However, it’s still 90% of the game.

I took my ball and went home. . .while I can still see.  Wrong game, wrong town, probably wrong life. . .but not my most pressing problem. Ray

Response:

"Donald Singleton" <donal…@sprynet.com> wrote: >To all, >    I emailed Ray Bonar last week asking him if he’d run the issue of ideal >IOP levels past Dr. Ritch for our edification, and today the following was >forwarded to me: >"Hi Ray >"The 22 mmHg dividing line was a statistical derivation from the 1950s >which held sway for a generation.  The definitions are presently in flux.

The definitions of what?  Glaucoma?  Ocular hypertension?  Magical pressure threshold?  A fundamental value of the new medical culture, good as a sway-holder for the next generation? >If someone has an IOP of 40 and you lower it to 20, they should do all >right.  However, someone who is losing field at IOP 24 will probably not do >all right in the long run with lowering to 20.  

Where is the evidence that lowering the 24 to 16 gives any better results than lowering it to 20 or leaving it alone? >What we condeptualize now >is that an IOP is too high if the patient loses field at that IOP, whatever >it is.  

Is this pure metaphysics, or does someone have theories compatible with non-medical reasoning and/or empirical supportable evidence as analyzed by such reasoning?  I’ve kind of had it with medical (particularly glaucoma-specialistic) "conceptualization" (fantasizing and justifying high income for low output). >For many patients, we are resetting target pressures to around 16, >rather than 21.  Obviously, if someone is losing field at 14, other, >non-pressure-dependent risk factors, are at play.  However, treating these >is still in its infancy.

So if there’s no better song in the air, beat the tom-toms faster and harder, right?  And ya gotta admit that the sun *is* still coming up, right?  All it takes is the right kind of musician, right?  Face the music, or face ostracism.  When will we ever come out of the jungle? Ray

Response:

Vernonh writes under "Re: Re desired IOP levels": >(NOTE-the below ramblings of an old optometrist mainly concern Primary >Open Angle Glaucoma-POAG)<

Ramble all you like–it’s interesting and informative. At the risk of excess  ramble myself (I plead guilty), hear are a few contributions. Good article by Jess Smith, MD, Baylor College of Medicine, Houston, TX, on  Diurnal Intraocular Pressure and its Correlation to Automated Perimetry. If I  am reading this properly, and I offer no guarantees since this is over my  non-professional head, it appears that patients with field defects have a mean  pressure of 22.1 with a range of 8 to 57, while those without defects have a  mean of 21.0 with a range of 8 to 50 (400 patients measured in each group, 800  total). Also, the diurnal variation in the first group was an astounding 20,  and in the second group, 19. (That raises the question for me as to how many  minutes per day each group of eyes is near the high end, and if, as you  suggest, there is a cutoff number, like 52, that is analagous to the freezing  or boiling point of water.)(It also tells me that decisions made on measuring  pressure in the same individual at different times of day raise questions; I  always try to schedule my appointments at the same time of day, except when I  was interested in my own variation.) Another interesting paper appears in Archives of Opthalmology, Vol 96,  September 1978, on the Use of Discriminant Analysis in Identification of  Persons With Glaucomatous Visual Field Defects. One highlight was the major  significance of blood glucose levels in men. And still another article, Risk Factors for Central Retinal Vein Occlusion–The  Eye Disease Case Control Study Group, in the same publication, Vol 114, May  1996, underlines increased risk of damage in hypertensives, diabetics, and  open angles. Risks decrease with physical exercise, alcohol use (careful,  there), postmenopausal estrogen use in women and higher erythrocyte  sedimentation rates in women. (I found this article while searching for  studies of lab tests, etc., glaucoma patients might have in  common–unfortunately, it was not as complete as I wanted.) There’s a lot of information out there; I wish it could be pulled together in one summary.

Response:

vern…@aol.com (VernonH) wrote: …………… >There almost certainly is a "magic" number for the IOP for a given patient >at a given >moment.

Is that according to Sant

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