IOP: Managing the Fluctuation Factor
Jul 26, · But in terms of this pressure going up and down, I’m going to pose some questions on why it might be happening because we know problems in the eye have their systemic and metabolic roots. It could be due to stress, trauma, toxicity, inflammation, and even things like blood pressure issues, diabetes, and other vascular diseases. What Is Causing Changes in Your Eye Pressure? Changes in eye pressure may be caused by: Excessive or decreased aqueous production; Inadequate or increased aqueous drainage; Long-term use of certain medications, in particular corticosteroids; Eye trauma.
Current Style: Standard. For the first two years after I was diagnosed with glaucoma, I had my eye pressure checked once every six months. I was under the impression that eye pressure is fairly steady and that large fluctuations are unusual. I certainly did not expect that I would experience very large fluctuations in eye pressure within very short periods of time such as minutes. However, fluctuations in my eye pressure are something I have observed frequently over the course of collecting more than 18, eye pressure measurements.
I have seen my eye pressure almost double within about 10 what channel is doomsday castle on. I have also seen it nearly halve within about 10 or 15 minutes particularly as a result of exercise.
I what causes eye pressure to fluctuate prefer to minimize such fluctuations. In particular, I try to do everything I can to eliminate large upward fluctuations in my eye pressure. So I am seeing these large changes in spite of my efforts to minimize them. Sometimes I feel these fluctuations must be related to my unique situation.
After all, I have pigmentary glaucoma and it seems reasonable that people with primary open angle glaucoma POAG might experience something different. However, when What foods are ok for dogs mentioned this concept to an expert in the field, he said there was no reason to suspect differences of this nature between pigmentary glaucoma patients and those with POAG.
Therefore, my current assumption is that what percentage is 7 out of 8 glaucoma patients could experience the rapid fluctuations in eye pressure that I do.
A couple days ago a friend sent me some of her eye pressure measurements. At AM her eye pressure was She checked it again 12 minutes later and it had jumped to She was rushing to get ready to go to the airport and taking care of a few other things.
Even though her situation is very different from my own she has POAG, for exampleher eye pressure fluctuations reminded me of exactly the kinds of eye pressure fluctuations I see in my own monitoring. There have been days when I have measured my eye pressure over times because I wanted to really understand the nature of quick changes like this. Some times I have collect 10 or even 18 measurements in rapid-fire succession while trying to monitor the rate of change in my eye pressure.
After collecting so many eye pressure measurements, I recognize a very clear pattern. It is important to note that I use a Reichert AT tonometer for most of my eye pressure measurements. This is a non-contact tonometer. This particular tonometer has been shown to be comparable to Goldman applanation tonometry. It is considered very accurate, with a small caveat or two. In particular, when eye pressure is very low, the AT seems to report a lower value than Goldman and when eye pressure is above normal, the AT seems to report a higher value than Goldman.
I think it is impossible to say which instrument is giving the more accurate value in these cases, but I do believe one sees a larger range of eye pressure values when using a non-contact tonometer for eye pressure measurements. In regard to eye pressure, the most unexpected situation I can imagine is for my eye pressure to be unchanged at different times of the day or what does eretz yisrael mean different circumstances.
Everyone knows blood pressure fluctuates with the conditions of the moment, but my eye pressure fluctuates far more than my blood pressure.
I assume that is related to the fact that I have glaucoma. I recently learned about the methods used in the Quaranta study to calculate a diagnostic value called diastolic ocular perfusion pressure DOPP. Diastolic ocular perfusion pressure is simply the difference between diastolic blood pressure the bottom number and eye pressure. In the eye, critical areas such as the optic nerve head can be deprived of blood flow if the eye pressure becomes too high in relationship to the blood pressure.
In other words, even if one has normal eye pressure, low blood pressure could result in critical structures in the eye such as the optic nerve head receiving inadequate perfusion.
That's why researchers are looking at the relationship between eye pressure and blood pressure. Of course, it is the instantaneous difference in these pressures that determines perfusion. Comparing average values of these two pressures could be meaningless if ocular perfusion changes over a range of values. It has been proposed that vascular risk factors are among the major precipitating factors that lead to the death of optic nerve cells in glaucoma, so the difference in blood pressure and eye pressure is of great importance.
Again, since it is the relationship between these two pressures at any moment in time that matters, comparing my blood pressure from yesterday afternoon with my eye pressure from today seems meaningless. Yet that is exactly what was done in the Quaranta study - the diastolic blood pressure and the eye pressure were measured on two different days.
These temporally unrelated values were used to calculate a number that is only valid for the relationship between two pressure measurements taken at the same time.
I would like to learn more about why the particular methodology used in the Quaranta study what causes eye pressure to fluctuate employed. I assume it may have been used because it has been reported that the eye maintains perfusion over a range of values until a threshold is reached. Furthermore, I tend to question whether the relationship between blood pressure and eye pressure matters only above a threshold and whether that threshold is a constant. Login or Create an Account to start interacting with the FitEyes community.
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Jun 14, · Recent research shows pressure variations over multiple visits and in the very early stages of glaucoma do not seem to correlate with progression. 1 This result could be because this variation was noted over months, and these eyes were at a very early stage of glaucoma.". What Causes High Eye Pressure? Excessive aqueous production. The aqueous (or aqueous humor) is a clear fluid that is produced in the eye by the ciliary Inadequate aqueous drainage. If the aqueous drains too slowly from the eye, disrupting the normal balance of production Certain medications. Feb 09, · A few conditions can cause pressure behind the eye, including: sinus problems headaches Graves’ disease damage to the optic nerve tooth pain.
Toggle navigation Clinical advice you can trust. One of the many mysteries remaining in our understanding of glaucoma is the behavior of intraocular pressure over time. We know that pressure fluctuates to some degree in an eye subjected to changing forces over the course of a day; unfortunately, the devil is in the details.
Unanswered questions include: How much does IOP fluctuate over the course of a day? Does the fluctuation follow a repeating pattern? How much does the fluctuation affect the course of glaucoma if it affects it at all? Can we measure such change effectively? And what can we do clinically to mitigate pressure fluctuation? Here, three experts discuss their recent findings and thoughts on what clinical protocols make the most sense in light of our current understanding.
Does Fluctuation Matter? One of the first questions that arises when considering fluctuating pressure inside the eye is: How much negative effect does fluctuating pressure have on the health of the eye—if any? The discussion is complicated by the fact that fluctuation can be seen as taking place over different time scales; very short-term, high-frequency fluctuations; diurnal fluctuation over the course of a day; and long-term fluctuation over months or years.
Any conclusions about the nature and impact of fluctuation have therefore been largely based on very sketchy evidence. Ironically, the evidence regarding the impact of diurnal and long-term fluctuation is mixed. Realini notes that if IOP fluctuation is eventually proven to contribute to glaucoma progression, that will create a clinical dilemma.
Number one, what does it mean? New tools under development may eventually enable us to monitor human IOP continuously, but in the meantime recent advances have allowed continuous monitoring of IOP in monkeys.
That data is revealing some surprising things. Bioengineer J. He has conducted research on this issue with Claude F. Burgoyne, MD, at Devers, using the primate experimental glaucoma model, as well as with Christopher A. Girkin, MD, head of the glaucoma service at the University of Alabama at Birmingham, in human subjects. Downs and his collaborators have become very interested in uncovering what is happening with IOP on a second-to-second time scale i. His current project with Dr.
Burgoyne is designed to shed light on how the optic nerve head reacts to IOP and what may make people more or less susceptible to the various levels of IOP and its fluctuations. In this case, the IOP transducer is implanted in the orbital wall with a tiny silicone tube protruding into the anterior chamber See picture, right ; the transmitter is implanted in the abdomen of the animal underneath the musculature.
Those measurements, performed by Dr. Burgoyne, generated IOP spikes 12 to 25 mmHg above baseline. We videoed the animals during these events, and they were not rubbing their eyes or squinting or doing anything else that would cause these pressure spikes. Downs says that overall, the amount of IOP variation they are finding is striking. Downs notes that he and Dr.
Burgoyne were not expecting these findings. Monkeys sleep sitting up. What About Humans? Downs notes that an early study by D. Their data suggests that blinking generates about 10 to 20 mmHg of brief pressure elevation; a forced squint raised an IOP of about 15 to 80 mmHg; and eye rubbing raised the pressure as high as to mmHg.
Like Dr. Downs, Sanjay G. We rub our eyes, we cough and sneeze. On the other hand, if the cells are pressured for an hour or two, their recovery of function is impeded. And this makes sense. Asrani notes that increased IOP as a result of lying down to sleep for eight hours might be considered a longer-term IOP increase.
Asrani adds that if this pressure compensation is real, it might undercut the potential impact of a nocturnal rise in pressure—or at least whatever part of such an increase could be attributed to the change in position from sitting up to lying down. Are Fluctuation Patterns Consistent? Because attempts to measure fluctuation are currently based on snapshot IOP measurements, extrapolation is required in order to draw any conclusions. That necessitates making certain assumptions about patterns that fluctuation follows, and recent data is casting doubt on some of those assumptions.
What is the IOP at different times? In hopes of helping to answer some of these questions, Dr. Realini has completed several studies that measured the IOP cycle in glaucomatous and healthy patients. Does it tell us anything about diurnal IOP behavior on other days? Realini says that two of their studies found very poor repeatability of the diurnal IOP curve shape in glaucoma patients.
This could have ramifications for both clinicians and researchers who are trying to measure IOP at standardized times of day in an attempt to remove diurnal variability from the equation. In fact, another similar study presented at the Association for Research in Vision and Ophthalmology meeting this year found the same thing.
Realini notes that the reasons for this are debatable. However, the repeatability of the diurnal IOP curve in the healthy subjects was equally bad. The same technician used the same tonometer and technique on each patient at every time point. Retrospective IOP studies are notoriously problematic because of variations in these factors, so we did our best to eliminate them.
We looked at this in both normals and glaucoma patients. However, the range of IOP showed uniformly poor agreement in a given eye from day to day, for both groups. Sit in one place. And we know that when you wake someone up, IOP goes up—even in healthy individuals. Despite all of these caveats, one fact about fluctuation that most doctors seem to agree upon is that large fluctuations are a characteristic of glaucoma, giving it some diagnostic value.
For example, Dr. To get a sense of the extent of fluctuation, Dr Asrani has patients return several times over a period of months at different times of day. On the other hand, if a patient has advanced glaucoma, time is of the essence—so I may have him return to complete a series of multiple measurements within a few weeks. In fact, one of the ways we determine that someone has NTG is that his pressures are not stable from visit to visit.
We published an article about that last year. On the other hand, the more advanced the stage of glaucoma, the more prevalent these fluctuations become. Some patients with a suspicious-looking optic nerve will measure 14 mmHg at one visit, 21 mmHg at the next visit, and 7 mmHg at the visit after that.
Of course, this comes with the caveat that you have to have very reliable pressure readings, made with the same type of instrument at each visit. Asrani adds that the purpose of multiple readings at each visit is simply to feel confident that the measurement is accurate.
Range is one measure of IOP variability that a lot of clinicians probably use—maximum pressure minus minimum. Furthermore, IOP variability has been shown to be a risk factor for progression, and we have indirect evidence that reducing variability can reduce progression. Downs agrees that choosing glaucoma treatments that help to dampen fluctuations is an arguable premise.
If you get dampening of pressure fluctuations with no extra side effects, that seems like a win-win to me. Realini says his clinical approach is to try to address both mean IOP and fluctuation at the same time.
So the order varies from patient to patient. These data are generally based on measurements taken once every three to six months. Downs concludes. If you can get the best IOP reduction out there and other potential benefits as well, terrific.
But you should not compromise the IOP reduction in order to get a secondary benefit. Coleman DJ, Trokel S. Direct-recorded intraocular pressure variations in a human subject. Arch Ophthalmol ;— Effect of repeated IOP challenge on rat retinal function. IOVS ; Short-term repeatability of diurnal intraocular pressure patterns in glaucomatous individuals.
Ophthalmology ; Diurnal intraocular pressure patterns are not repeatable in the short term in healthy individuals. Clin Ophthalmol ; Comparing diurnal and nocturnal effects of brinzolamide and timolol on intraocular pressure in patients receiving latanoprost monotherapy.
Comparison of the nocturnal effects of once-daily timolol and latanoprost on intraocular pressure. Am J Ophthalmol ; Diurnal and nocturnal effects of brimonidine monotherapy on intraocular pressure. Effect of laser trabeculoplasty on nocturnal intraocular pressure in medically treated glaucoma patients.
A comparison of the intervisit intraocular pressure fluctuation after and degrees of selective laser trabeculoplasty SLT as a primary therapy in primary open angle glaucoma and ocular hypertension. J Glaucoma ; Effect of trabeculectomy on intraocular pressure fluctuation with postural change in eyes with open-angle glaucoma. Long-term intraocular pressure fluctuation and progressive visual field deterioration in patients with glaucoma and low intraocular pressures after a triple procedure.