SA and eye diseases

[idamtnboy]

Had my annual eye exam today. I asked the Dr. if there is any connection between sleep apnea and eye diseases. "You bet, glaucoma."
Here are some quotes I found doing a Google search.

This is from a Spanish medical paper that is listed on PubMed.gov, an NIH library program.

Abstract
Sleep apnea syndrome is characterised by recurrent episodes of partial or complete upper airway flow interruption during sleep. In the last twenty years, the relationship of sleep apnea with cardiovascular disease has been recognised. More recently, several ocular disorders have been associated with sleep apnea syndrome, including floppy eyelid syndrome, glaucoma, non-arteritic ischemic optic neuropathy and papilledema. Based on the published evidence, we discuss these associations along with the possible pathophysiological mechanisms and clinical management. It is needed that the ophthalmologist, the primary care physician and the sleep physician are aware of this association so that both sleep disorders and the related ophthalmologic disorders can be better diagnosed and treated.

From the article, "One Third of Sleep Apnea Patients in Study Diagnosed With Glaucoma" on Medscape.

Patients with OSA are already known to be at higher risk for motor vehicle collisions, myocardial infarctions, strokes, and premature death. "Perhaps glaucoma will one day be added to this list," Dr. Bendel said.

From another paper listed on PubMed.

The Association between Glaucomatous and Other Causes of Optic Neuropathy and Sleep Apnea.
Stein JD, Kim DS, Mundy KM, Talwar N, Nan B, Chervin RD, Musch DC.
Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
Abstract
PURPOSE:

To determine whether an association exists between sleep apnea and open-angle glaucoma, normal-tension glaucoma, nonarteritic ischemic optic neuropathy (NAION), papilledema, or idiopathic intracranial hypertension (IIH) and whether treatment with continuous positive airway pressure affects the development of these conditions.

CONCLUSIONS:

Patients with untreated sleep apnea are at increased risk for IIH and NAION. Clinicians should consider appropriate screening for these conditions in sleep apnea patients.

Most all the articles I found are medical journal type articles, and thus are not available for free and of course are written in medical-ese. But what I glean from all this is that OSA is a significant contributor to eye diseases, especially glaucoma and more frighteningly, to optic nerve damage. Screw up the optic nerve and you really screw up vision.

Another reason to stick with xPAP therapy. Minimize the possibility of going blind! Maybe this is a bit over dramatic, but you get the point.

[robysue]

Unfortunately, the connection between OSA and glaucoma is not quite so simple as you make it out. Yes, there seems to be a connection between OSA itself and higher then normal risk of glaucoma. But this 2008 paper, published in Investigative Opthamology and Visual Science describes a study that contains disturbing data that show CPAP therapy itself can significantly raise intraocular pressure in OSA sufferers.

The authors of the paper state:

As far as we know, this study represents the first analysis of the circadian IOP course in a series of patients with OSA at baseline conditions and during CPAP therapy.

and the Conclusion of the paper states:

An overnight increase in IOP (intraocular pressure) is present in patients with OSA. During CPAP therapy, nocturnal IOP increases even more prominently and is paralleled by a decrease in OPP (ocular perfusion pressure). This could be one of the factors responsible for the higher prevalence of glaucoma in this population. Whether long-term CPAP use has a deleterious influence on the development or progression of glaucoma should be investigated further. Evaluation and follow-up of the IOP, optic disc, and visual fields warrants attention in the clinical work-up of all patients with OSA, especially those treated with CPAP.

This study was a small one. And hence it's hardly conclusive. But it was well constructed: The authors studied a total of 21 newly diagnosed OSA patients. Prior to the patients' starting CPAP therapy (but after the OSA diagnosis), each patient went through a complete eye exam and then a 24 hour study where their IOPs were measured every 2 hours while the patients were lying on their backs. The study was repeated one month after the patients started CPAP therapy. During the night portion of the repeat study, the patients used their CPAPs as prescribed. Of the 21 patients, one patient had a prior diagnosis of normal tension glaucoma at the start of the study; the other 20 patients all had normal discs and normal vision fields at the time of their OSA diagnosis.

The results of the study? As a group, the patients all had statistically significant greater than normal fluctuations in IOP during the baseline, pre-CPAP study, with the highest IOPs occurring at night. One month after starting CPAP, all 21 patients' nocturnal IOPs were significantly higher during a night they were using CPAP than their nocturnal IOPs had been on the pre-CPAP study. As a group, there was no statistical difference between the daytime IOPs before CPAP and one month into CPAP. And the authors point out that the elevated nocturnal IOPs on CPAP appear to return to the baseline no-CPAP IOPs within 30 minutes of ending CPAP therapy in morning. So the increase in nocturnal IOP does seem to be caused by the use of CPAP. Notably four of the 20 patients who did not have normal tension glaucoma at the beginning of study were diagnosed with ocular hypertension with no optic disc excavation or visual filed defects after the CPAP IOP study. These four patients were put on prescription medicine for their ocular hypertension---presumably some kind of eye drops that are used in the treatment of glaucoma.

I can't help but wonder if any additional study of long-term CPAP use on the development or progression of glaucoma has been done. And if so, what was found.

I also can't help but wonder how many CPAPers get visual field screening as part of their eye exams: Unlike measuring the IOP and examining the optic disc during the split lamp exam, visual field screening is NOT a part of a typical "routine" eye exam. I also wonder how many OSA patients are told by either their sleep docs or their eye docs that OSA is a risk factor for glaucoma and that CPAP may increase that risk, and that a baseline visual field test is a good idea.

I bring all this up this as someone who has been diagnosed as a glaucoma suspect in July 2011 --- approximately 10 months after I started PAP therapy. So for the time being, I've got to go get a pressure check, a slit lamp exam AND a visual fields exam every 3--4 months. And it will likely continue that way until I do get diagnosed with glaucoma or my eyes remain stable for a long enough time for the eye doc to start stretching out those follow-up visits a little at a time.

And notably, I had a normal complete eye exam in July 2010 --- approximately 2 months before starting CPAP therapy in Sept. 2010. So do I wonder if CPAP led to my status as a "glaucoma suspect"? Of course I do. And in the 10 months of CPAP before my suspect eye exam, neither sleep doc nor neither of the PAs who saw me (multiple times) ever mentioned that I might be at risk for eye problems. And do I wish they'd mentioned it? Yes, I do wish they'd said something.

And of course, the worry-wart in me has added this to the long standing, but unanswered question: "Just what are the long-term side effects and risks of xPAP?" It's not that I expect or intend to stop xPAP. It's just that I would prefer to know what kinds of things I need to be careful about.

[idamtnboy]

Unfortunately, the connection between OSA and glaucoma is not quite so simple as you make it out.

You're right. I quickly got the feeling that study results and correlations are not clear cut while I was scanning through the dozens of abstracts I found. But my intent was more to raise awareness of an issue that I was not even aware of until yesterday. I didn't delve into it but apparently there is more than one condition in the glaucoma disease group. SA apparently is not a huge factor in normal-tension glaucoma, which I take to be the mildest form. But it appears there is quite a bit stronger correlation between SA and open-angle glaucoma, whatever that is. But what really got my attention was the repeated mention of SA and optic nerve issues.

I can't help but wonder if any additional study of long-term CPAP use on the development or progression of glaucoma has been done. And if so, what was found.

The need for additional studies was a recurrent comment in the abstracts I looked at.

I also can't help but wonder how many CPAPers get visual field screening as part of their eye exams: Unlike measuring the IOP and examining the optic disc during the split lamp exam, visual field screening is NOT a part of a typical "routine" eye exam. I also wonder how many OSA patients are told by either their sleep docs or their eye docs that OSA is a risk factor for glaucoma and that CPAP may increase that risk, and that a baseline visual field test is a good idea.

Good question. I know visual field screening was not a regular part of my annual exams until just 5 years ago. I just assumed that the advent of computerized scanning is the only reason it has become common. My conversation with the Dr yesterday, which I initiated by mentioning that CPAP was part of my current medical history, is the first time any eye doctor has said anything about SA and eye problems. The sleep Dr and my PCP have not said anything about SA and eye problems. The Dr yesterday asked his technician to perform an OptoMap scan of my retinas as an afterthought just before I left the office. We had discussed doing the Optomap earlier but I opted to not have it done as we did it last year and it would cost me an additional $30 not covered by insurance. Dilation was the alternative option. I kind of think he decided that he ought to have the OptoMap scan in the file because of the issue of SA and CPAP and so did not charge me for it.

I bring all this up this as someone who has been diagnosed as a glaucoma suspect in July 2011 --- approximately 10 months after I started PAP therapy. So for the time being, I've got to go get a pressure check, a slit lamp exam AND a visual fields exam every 3--4 months. And it will likely continue that way until I do get diagnosed with glaucoma or my eyes remain stable for a long enough time for the eye doc to start stretching out those follow-up visits a little at a time.

And notably, I had a normal complete eye exam in July 2010 --- approximately 2 months before starting CPAP therapy in Sept. 2010. So do I wonder if CPAP led to my status as a "glaucoma suspect"? Of course I do.

I'm inclined to think age is the greater contributor to the change.

And of course, the worry-wart in me has added this to the long standing, but unanswered question: "Just what are the long-term side effects and risks of xPAP?"

I think I saw that sentiment expressed in some of the abstracts, so I would say at least some professionals in the field are thinking about it.

[Goofproof]

Having Sleep Apnea can contribute to most health problems, it doesn't mean it's the cause of our health problems. Sometimes Hair Loss, and Hangnails arent there because of Sleep Apnea. We treat what we can and go on trying to live. Jim

[Vader]

Another important procedure is glaucoma evaluation is to make sure you have a corneal thickness test.
Abnormally thick corneas can give a false positive test result. People with abnormally thin corneas could have a higher occular pressure than what conventional testing indicates.
I found this out because I was wrongly indicated for glaucoma over twenty years ago.

[chunkyfrog]

Vader: so right about the corneal thickness.
There is also a roundabout correlation--Excess trunk pressure.
After I lost 30 pounds, my opthalmologist informed me that he no longer had to
deduct for my added pressure from obesity when I leaned forward into the machine.
As we all know apnea and obesity often occur together--(chicken or egg thing)
--My opinion: At least for me, the apnea came first.
But apnea causing glaucoma?--I was diagnosed with glaucoma in 1992; apnea in 2010.
My case only--not scientific in any way; but worth some more research.

[idamtnboy]

But apnea causing glaucoma?--I was diagnosed with glaucoma in 1992; apnea in 2010.
My case only--not scientific in any way; but worth some more research.

The way I read it, the studies are showing that sleep apnea is one of the causes of, or aggravates, glaucoma, but certainly not the only one.

[BlackSpinner]

Well since it is the choice of some glaucoma or having a stroke or being dead, I will take the glaucoma.

[chunkyfrog]

--Especially since the glaucoma is usually quite treatable; sometimes pleasantly so.
Unfortunately, the powers that be in corn country will not allow medical cannabis.

[robysue]

SA apparently is not a huge factor in normal-tension glaucoma, which I take to be the mildest form. But it appears there is quite a bit stronger correlation between SA and open-angle glaucoma, whatever that is. But what really got my attention was the repeated mention of SA and optic nerve issues.

Open angle gluacoma is the most common type of glaucoma diagnosed here in the states. My understanding is that open angle glaucoma is diagnosed when the IOP is higher than normal AND there are changes in the visual appearance of the optic nerve indicating optic nerve damage. When enough damage has occurred, this affects the the visual field---i.e. you start to slowly lose your peripheral vision. If the IOP is elevated but the optic nerve still visually looks "normal", you probably will be labeled as a "glaucoma suspect" and followed closely. If the IOP is really elevated, you may be put on eye drops even if the optic nerve still looks reasonably normal. Open angle glaucoma typically has no symptoms until enough of the visual field is lost for the loss of vision to become apparent. The "open angle" part of the name refers to the current theories about what causes the damage to the optic nerve. The idea is that the fluid in the eye does not drain correctly through the so-called "angle" at the bottom front of the eyeball even though this angle remains open in appearance---in other words, the problem with drainage is a bit farther "downstream" so to speak in the network of fine drainage channels below the "angle". As the fluid builds up in the eye, the IOP increases and the increased pressure starts to damage the optic nerve. Treatment for open angle glaucoma is one or more types of eye drops designed to reduce the IOP ---preferably all the way into the normal range. Some of the eye drops are designed to reduce the total amount of intraocular fluid produced by the eye; other drops help encourage the fluid to drain better through the congested drainage network. The idea behind the treatment is that if the IOP is reduced, that will take pressure off the optic nerve, and the damage will either be arrested (i.e. stopped) or slowed (i.e. so vision loss is minimized.)

I'm not sure why you think normal tension glaucoma is somehow "milder" than open angle glaucoma. Basically normal tension glaucoma is the diagnosis when you get when you have glaucomatous-type damage to the optic nerve but you do NOT have an abnormally high IOP when it is measured in the eye doc's office. And when enough damage has been done to the optic nerve, the visual field is affected in the same way that open angle glaucoma affects the visual field. As in open angle glaucoma, the angle at the front of the eye remains open. One theory is that folks with normal tension glaucoma have optic nerves that are simply much more sensitive to fluctuations and "high normal" IOP than folks with normal eyes. Alas, the treatment for normal tension glaucoma is the same as open angle glaucoma: Eye drops to reduce the IOP even though the IOP at the time of measurement is in the normal range. The hope is that reducing that normal IOP to an even lower normal IOP will prevent further damage to the optic nerve.

Typically if the IOP is in the normal range and there's been a change in appearance in the optic nerve indicating possible glaucomatous damage, you get labeled a "glaucoma suspect" and you're followed closely. At the follow up appointments, the doc is looking for either a rise in eye pressure into the abnormal range (and you get diagnosed with open angle glaucoma) or visual evidence of on-going deterioration in the appearance of optic nerve when inspected during the slit lamp exam (and you get diagnosed with normal tension glaucoma) or a deterioration in the visual field (and you get diagnosed with normal tension glaucoma.) As long as the IOP remains normal, the visual appearance of the optic nerve remains stable, and the visual field remains normal, you simply remain a "glaucoma suspect" and you continue to be followed closely.

And notably, I had a normal complete eye exam in July 2010 --- approximately 2 months before starting CPAP therapy in Sept. 2010. So do I wonder if CPAP led to my status as a "glaucoma suspect"? Of course I do.

I'm inclined to think age is the greater contributor to the change.

Age is not supposed to be a big factor until you reach 60. I'm still in my early 50s. Family history is supposed to be a factor, but no-one in my family (including parents and grandparents) has had glaucoma.

[robysue]

Well since it is the choice of some glaucoma or having a stroke or being dead, I will take the glaucoma.

The authors in the 2008 paper understand the importance of CPAP therapy for OSA sufferers. They state at the end of the Discussion section, "If glaucomatous changes or elevated IOP are discovered or develop during CPAP therapy, topical IOP lowering therapy can be started. CPAP withdrawal is not an option, due to the dramatic overall improvement of subjective sleepiness, quality of life, and cognitive functions in patients with OSA treated with CPAP (emphasis added)." And of course, IF you tolerate the daily eyedrops well and IF the damage to your eyes stabilizes before it leads serious deterioration of your vision, then sure, the benefits of CPAP clearly outweigh the risks. But 10% of glaucoma patients who receive appropriate medical treatment still experience some vision loss from their treated glaucoma. (source: http://www.glaucoma.org/glaucoma/glauco ... -stats.php).

In any case, it seems prudent to inform new CPAPers that they should get a thorough baseline eye exam including a visual field test done at the time they start xPAP therapy and that they really do need to schedule yearly complete eye exams including a visual field test so that IF the xPAP does trigger an increase in IOP, then the increased IOP is caught early and there is already a baseline visual field test for detecting whether any damage has already occurred by the time the IOP is detected. (And note: The authors of that 2008 paper seem to indicate that all CPAPers may need complete eye exams with visual field testing more frequently than once a year. And many, many people do NOT get annual eye exams----particularly if they don't wear glasses and have not had any eye problems.)

Medications must carry warnings concerning the very infrequent, but serious side effects that may develop as a result of taking them. (And the label for prednisone does contain this Precaution for long-term use: "Intraocular pressure may become elevated in some individuals. If steroid therapy is continued for more than 6 weeks, intraocular pressure should be monitored.") But manufacturers of CPAP machines do not need to provide us with any thing in writing concerning rare, but possible side affects or adverse reactions. And neither do our sleep docs. Now don't get me wrong: I think xPAP is a critically important therapy for us. It is life saving for many of us. And the benefits surely outweigh the risks (and inconveniences and nightly discomforts). But that doesn't mean there are no risks. And being kept in the dark about those risks is just as insulting as being told that a compliance data machine is all we need and that we should not to worry our pretty little heads about anything except making sure we use the machine every night.

--Especially since the glaucoma is usually quite treatable; sometimes pleasantly so.
Unfortunately, the powers that be in corn country will not allow medical cannabis.

Putting aside the issue of medical cannabis, it is important to note that patient compliance for glaucoma treatment is not very good: A large (almost 18,000 patients) long term in California showed "27% of the patients were poorly compliant, 31% were fairly complaint, and 31% were highly compliant." (Source: http://www.medscape.com/viewarticle/752251) The article goes on to quote an opthamologist who says, "The average patient takes about 8 different medications and sees a doctor at least once a month. That’s a big burden. It boils down to the fact that many patients don’t take all their medications." And the article also points out that the study revealed (to no-one's surprise) that compliance during the first year or two of treatment was a strong indicator of long term compliance.

So, yes, technically glaucoma is quite treatable---but it often takes multiple prescription drugs on a pretty rigorous dosing schedule. Learning how to put the eye drops in themselves also is not self-obvious and patient mistakes in getting the eye drops into the eyes is also a problem with compliance. Moreover, all of these drugs do have the potential to trigger side effects and some of those side effects can be serious. (Source http://www.glaucoma.net/nygri/glaucoma/topics/drugs.asp)

And getting back to cannabis: Not all of us found it pleasant to smoke it when we were young.

[SleepyT]

Interesting. My dad was diagnosed with SA earlier this year....and was told years ago he had glaucoma. He puts drops in his eyes daily to manage the glaucoma.

I learn something new every day on this forum.

[MaxDarkside]

This is an interesting thread, helpful to me. In May I was found to be a "glaucoma suspect" with high and uneven ocular pressures. I also have high blood pressure. I do have thick corneas which explain the higher pressure indications, but the unevenness still points to glaucoma. I had a tomography and a peripheral vision test (see a twinkling light, click a button) that were "normal" but during the peripheral vision test I could see vision degradation in the lower, nose side of my vision in the higher pressure eye, the typical place glaucoma starts to appear. It is good to know that xPAP increases your nocturnal ocular pressure, so on Tuesday I will book an IOP and maybe another peripheral vision recheck appointment (> 1 month now on SA treatment for me).

I have researched glaucoma quite a lot, though I'm not a doctor, I have learned quite a lot about it. To clarify some of the posts here, glaucoma is not treatable. IOP (ocular pressure) *is* treatable with eye drops (essentially high blood pressure medicine to the eyes) or surgery (drilling little tiny holes in your eyes to help them drain fluid better). Glaucoma is a neuro-degenerative disease of the optic nerve that can run from the retina into the brain from causes unknown and appears to be aggravated by high IOP, I'm guessing from two mechanisms; mechanical damage near the retina (cupping) and perhaps higher pressure along the optic nerve aiding other degenerative chemical processes. IOP is not a cause, because there are people with glaucoma with normal ocular pressure. Even with excellent pressure control, many people still go blind. High IOP appears to aggravate the condition. From what I read, there is a suspicion that glutamates and their relationship with Magnesium, Sodium and Calcium ions may be a cause, programming your optic nerve to self-destruct (a natural mechanism that occurs in fetuses to selectively destroy tissues to create fingers, toes, etc.). The research goes on...

Thanks!