Vision & CPAP

RipVW · Post by **RipVW** » Tue Feb 28, 2012 1:30 pm

Continuous Positive Airway Pressure Therapy Is Associated with an Increase in Intraocular Pressure in Obstructive Sleep Apnea

PURPOSE. Several reports have demonstrated an association between glaucoma and obstructive sleep apnea (OSA), though the origin of this association remains unknown. In the present study, the influence of OSA and continuous positive airway pressure (CPAP) therapy on intraocular pressure (IOP) and ocular perfusion pressure (OPP) was examined.

METHODS. IOP, blood pressure, and pulse rate were measured every 2 hours during 24-hour sessions in 21 patients with newly diagnosed OSA. A first series of measurements was performed before CPAP therapy, and a second series was performed 1 month after the initiation of CPAP therapy. OPP was then calculated.

RESULTS. Baseline measurements showed a significant nycththemeral fluctuation in the average IOP, with the highest IOPs at night. After 1 month of CPAP therapy, the average IOP was significantly higher than baseline. The increase in overnight IOP was also significantly higher. A 24-hour IOP fluctuation of 8 mm Hg was found in 7 patients at baseline and in 12 patients during CPAP therapy. The mean difference between trough and peak IOP was 6.7 ± 1.5 mm Hg at baseline and 9.0 ± 2.0 mm Hg during CPAP therapy. Thirty minutes after CPAP cessation a significant decrease in IOP was recorded. There was a statistically significant decrease in mean OPP during CPAP therapy.

CONCLUSIONS. Patients with OSA demonstrated significant 24-hour IOP fluctuations, with the highest values at night. CPAP therapy causes an additional IOP increase, especially at night. Regular screening of visual fields and the optic disc is warranted for all patients with OSA, especially those treated with CPAP.

Stefan Kiekens,1 Veva De Groot,1 Tanja Coeckelbergh,1 Marie-José Tassignon,1 Paul van de Heyning,2,3 Wilfried De Backer,3,4 and Johan Verbraecken3,4

1From the Departments of Ophthalmology, 2Ear, Nose and Throat, and 4Pulmonary Medicine, and the 3Sleep Disorders Center, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium.
from http://www.iovs.org/cgi/content/abstract/49/3/934

JohnBFisher · Post by **JohnBFisher** » Tue Feb 28, 2012 1:36 pm

Though I already have regular checkups with my optometrist, this article essentially notes that it is important even for those folks who would not otherwise regularly see an eye doctor to do so if they use xPAP therapy.

Thanks for finding that article for us.

Kairosgrammy · Post by **Kairosgrammy** » Tue Feb 28, 2012 1:39 pm

*sigh* It's always something isn't it. Get one problem fixed and another possible problem pops up. I'll be sure to talk with eye doctor on my next appt about this particularly since my pressure was recently raised.

RipVW wrote:Continuous Positive Airway Pressure Therapy Is Associated with an Increase in Intraocular Pressure in Obstructive Sleep Apnea

PURPOSE. Several reports have demonstrated an association between glaucoma and obstructive sleep apnea (OSA), though the origin of this association remains unknown. In the present study, the influence of OSA and continuous positive airway pressure (CPAP) therapy on intraocular pressure (IOP) and ocular perfusion pressure (OPP) was examined.

METHODS. IOP, blood pressure, and pulse rate were measured every 2 hours during 24-hour sessions in 21 patients with newly diagnosed OSA. A first series of measurements was performed before CPAP therapy, and a second series was performed 1 month after the initiation of CPAP therapy. OPP was then calculated.

RESULTS. Baseline measurements showed a significant nycththemeral fluctuation in the average IOP, with the highest IOPs at night. After 1 month of CPAP therapy, the average IOP was significantly higher than baseline. The increase in overnight IOP was also significantly higher. A 24-hour IOP fluctuation of 8 mm Hg was found in 7 patients at baseline and in 12 patients during CPAP therapy. The mean difference between trough and peak IOP was 6.7 ± 1.5 mm Hg at baseline and 9.0 ± 2.0 mm Hg during CPAP therapy. Thirty minutes after CPAP cessation a significant decrease in IOP was recorded. There was a statistically significant decrease in mean OPP during CPAP therapy.

CONCLUSIONS. Patients with OSA demonstrated significant 24-hour IOP fluctuations, with the highest values at night. CPAP therapy causes an additional IOP increase, especially at night. Regular screening of visual fields and the optic disc is warranted for all patients with OSA, especially those treated with CPAP.

Stefan Kiekens,1 Veva De Groot,1 Tanja Coeckelbergh,1 Marie-José Tassignon,1 Paul van de Heyning,2,3 Wilfried De Backer,3,4 and Johan Verbraecken3,4

1From the Departments of Ophthalmology, 2Ear, Nose and Throat, and 4Pulmonary Medicine, and the 3Sleep Disorders Center, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium.
from http://www.iovs.org/cgi/content/abstract/49/3/934

F3adventure · Post by **F3adventure** » Tue Feb 28, 2012 9:05 pm

RipVW's post to me was a little like reading an article in Spanish. I recognized enough of the words to get the gist, but that's about it!

The first thing I noticed when I started treating my apnea was that my vision was blurry in the morning. I had a hard time reading the screen on my machine, which was a little abnormal to me. It seemed after an hour or two my vision would clear a little, but it feels like I have seen a step change down in my vision overall since I started using a machine. I had discounted the correlation between therapy and vision impairment until now.

I have been considering getting my eyes examined. I wonder how many eye doctors are familiar with XPAP therapy?

Do any of you forum members have any experience with this?

unsuspected Severe OSA · Post by **unsuspected Severe OSA** » Tue Feb 28, 2012 11:22 pm

Thanks, Rip for posting the article. In the post, Long-term Effects, Lizitired bought up the link in reference to my concern about glaucoma and corneal dryness from the CPAP. It's interesting that these Belgian researchers recommend visual fields, plus the usual eye pressure (IOP) testing and looking at the optic disc. Since the pressure hits the peak during the night of CPAP, they are being very cautious to detect damage even if your IOP is normal during your day office apt. We will most likely have to request this exam, but it's worth detecting as high IOP can be easily treated with eye drops and prevent glaucoma damage of blind spots.

RipVW · Post by **RipVW** » Wed Feb 29, 2012 4:58 pm

unsuspected Severe OSA wrote:Thanks, Rip for posting the article. In the post, Long-term Effects, Lizitired bought up the link in reference to my concern about glaucoma and corneal dryness from the CPAP. It's interesting that these Belgian researchers recommend visual fields, plus the usual eye pressure (IOP) testing and looking at the optic disc. Since the pressure hits the peak during the night of CPAP, they are being very cautious to detect damage even if your IOP is normal during your day office apt. We will most likely have to request this exam, but it's worth detecting as high IOP can be easily treated with eye drops and prevent glaucoma damage of blind spots.

You're welcome! So much to learn--fix one thing, possibly break another thing! I know I'll make this known and request these additional screenings during my next visit with the eye doc.

kteague · Post by **kteague** » Wed Feb 29, 2012 5:18 pm

As a glaucoma patient, that interests me. Thanks for posting this. Already had an appointment coming up and will mention that to the eye doc.

Resister · Post by **Resister** » Wed Feb 29, 2012 5:33 pm

In English, please? LOL, I'm trying to wade through it, but it's hard with the normal chaos.

My vision has been getting blurrier over the last few months, but when I went in for a quick check the doc told me my prescription hasn't changed. She did, however, mention part of my situation was part of getting older.

robysue · Post by **robysue** » Wed Feb 29, 2012 9:23 pm

The links between glaucoma, OSA, and CPAP have been discussed here before. One relevant link is this thread: viewtopic.php?f=1&t=70317&p=651116&

In that thread I brought up the paper that the OP cites in the original post in this thread. I also gave this link to the full paper instead of just the abstract.

The upshot of this article seems to be a careful description of 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.

The authors of the 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).

Finally the authors of this paper seem to indicate that all CPAPers may need complete eye exams with visual field testing more frequently than once a year.

In any case, it seems prudent to me that sleep docs should 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. But unfortunately many, many people do NOT get annual eye exams----particularly if they don't wear glasses and have not had any eye problems.

robysue · Post by **robysue** » Wed Feb 29, 2012 9:47 pm

Resister wrote:In English, please? LOL, I'm trying to wade through it, but it's hard with the normal chaos.

My vision has been getting blurrier over the last few months, but when I went in for a quick check the doc told me my prescription hasn't changed. She did, however, mention part of my situation was part of getting older.

The long version is in my previous post.

The short version is: The study was a small one that found that in a selected group of 21 OSA patients. Patients' intra ocular pressure (IOP) was measured every 2 hours for a 24 hour period---once after they were diagnosed with OSA, but before they started CPAP and once after they'd been using CPAP for a month. All 21 members of the study group showed greater than normal fluctuations in IOP before starting CPAP, with the highest IOP at night. And after a month on CPAP, the peak, night time IOP was STATISTICALLY HIGHER on the night CPAP was used than the peak night time IOP had been prior to starting CPAP. One of the members of study group had a prior diagnosis of normal tension glaucoma before starting CPAP treatment. The other 20 patients had no history of elevated IOP or glaucoma in their medical history. Four of these 20 patients were diagnosed with clinically significant high IOPs after a month on CPAP and were put on eye drops to reduce the IOP pressure. They apparently did not yet have visual changes to their optical disks or visual field tests.

Because the CPAP users nocturnal IOPs significantly increased once they were using CPAP, the authors speculate that CPAP use may be one factor that explains a higher than expected incidence of glaucoma in OSA patients using CPAP.

Because the study was a small scale study, the authors suggest that the connections between CPAP use, a possible increase in nocturnal IOP, and the development of glaucoma need to be studied further.

And because all the study subjects experienced a statistically significant increase in their nocturnal IOPs while on CPAP, the authors prudently recommend regular, complete eye exams---including both an IOP reading AND a visual field test---for all newly diagnosed OSA patients before they start CPAP and at regular intervals for CPAP users---at a minimum of once a year, but perhaps more frequent eye exams---so that any glaucomatous changes can be caught early and properly monitored (if they only fall into the category of "glaucoma suspect") or treated (if they warrant a diagnosis of glaucoma itself.)

So the question to ask is: Did that "quick check" of your vision include: An IOP test, a slit-lamp exam (where the doc can see the optic nerve itself), and a vision-field test?

KrisasMan · Post by **KrisasMan** » Wed Feb 29, 2012 9:53 pm

It would be interesting to see the results of a larger study to see if the therapy pressure level has an effect on risk. It would make sense that the higher the level the greater the risk. It would also be interesting to see if there is a risk difference between CPAP with continuous pressure and an APAP.

As a relatively young starter on CPAP I will have to keep an eye on this

Resister · Post by **Resister** » Wed Feb 29, 2012 10:07 pm

robysue wrote:
Resister wrote:In English, please? LOL, I'm trying to wade through it, but it's hard with the normal chaos.

My vision has been getting blurrier over the last few months, but when I went in for a quick check the doc told me my prescription hasn't changed. She did, however, mention part of my situation was part of getting older.
The long version is in my previous post.

The short version is: The study was a small one that found that in a selected group of 21 OSA patients. Patients' intra ocular pressure (IOP) was measured every 2 hours for a 24 hour period---once after they were diagnosed with OSA, but before they started CPAP and once after they'd been using CPAP for a month. All 21 members of the study group showed greater than normal fluctuations in IOP before starting CPAP, with the highest IOP at night. And after a month on CPAP, the peak, night time IOP was STATISTICALLY HIGHER on the night CPAP was used than the peak night time IOP had been prior to starting CPAP. One of the members of study group had a prior diagnosis of normal tension glaucoma before starting CPAP treatment. The other 20 patients had no history of elevated IOP or glaucoma in their medical history. Four of these 20 patients were diagnosed with clinically significant high IOPs after a month on CPAP and were put on eye drops to reduce the IOP pressure. They apparently did not yet have visual changes to their optical disks or visual field tests.

Because the CPAP users nocturnal IOPs significantly increased once they were using CPAP, the authors speculate that CPAP use may be one factor that explains a higher than expected incidence of glaucoma in OSA patients using CPAP.

Because the study was a small scale study, the authors suggest that the connections between CPAP use, a possible increase in nocturnal IOP, and the development of glaucoma need to be studied further.

And because all the study subjects experienced a statistically significant increase in their nocturnal IOPs while on CPAP, the authors prudently recommend regular, complete eye exams---including both an IOP reading AND a visual field test---for all newly diagnosed OSA patients before they start CPAP and at regular intervals for CPAP users---at a minimum of once a year, but perhaps more frequent eye exams---so that any glaucomatous changes can be caught early and properly monitored (if they only fall into the category of "glaucoma suspect") or treated (if they warrant a diagnosis of glaucoma itself.)

Thanks for clarifying! I will definitely mention this at the next visit.

So the question to ask is: Did that "quick check" of your vision include: An IOP test, a slit-lamp exam (where the doc can see the optic nerve itself), and a vision-field test?

PST · Post by **PST** » Wed Feb 29, 2012 11:12 pm

There is another eye condition that can cause blurred vision and may be made worse by CPAP. Epithelial basement membrane dystrophy (also known as map-dot-fingerprint) is an irregularity of the outer surface of the cornea characterized by abnormal features that evidently reminded some ophthalmologist who discovered it of maps, dots, and fingerprints. It leaves the cornea susceptible to injury, and the irregularities can cause blurring that eyeglasses won't correct. CPAP doesn't cause it (it's probably inherited), but a leaking mask can exacerbate the condition if it allows air to blow across the eyes. Many people with the condition have no symptoms, but if someone has started on CPAP and notices corneal pain or deterioration of vision, it is something else to ask the doctor about. I had no idea I had it until I scratched a cornea just rubbing my eyes. It's one of those things you don't really cure, but it can be treated easily so it doesn't cause much trouble.

unsuspected Severe OSA · Post by **unsuspected Severe OSA** » Thu Mar 01, 2012 6:09 pm

My 94 y/o mother has corneal dystrophy and her doctor informally checked me assuming that I would have it (some forms are autosomal dominant), but I did not within this past year, but before CPAP. After my first few months, I noticed the eyes were slightly dry, attributable to the exhaust air, so I'm using OTC eye ointment at night. My mother just uses Restasis, an immunosuppressive eye drop to decrease eye inflammation and stimulate tear production. Sounds like PST has controlled this eye condition despite CPAP; unlike my mother who battles with lubricants& antibiotics intermittently possibly due to the Restasis.

Lizistired · Post by **Lizistired** » Fri Mar 02, 2012 9:13 pm

After reading the study and doing some additional googling, I called a friend with OSA and asked if her eye doctor knew she had OSA and if he had ever discussed with her the increased incidence of Glaucoma in OSA patients. She said he had mentioned it and that he checked her pressure at annual appointments, though she didn't know much about it.

Well I haven't had an eye exam in about 10 years and I want to know why our sleep doctors don't even mention this!

My eyesight has been wacky for the last year or so, at least 3 months before my PSG. My friends don't understand why I carry multiple pairs of readers.... Because I need different ones at different times to see different things!!!! I'm making an appointment Monday.

I'm posting to vent, and to share an interesting site I found today: http://fiteyes.com/
For the data geeks here, one of the things they do is monitor their own eye pressure and what affects it, water, stress, caffeine, exercise(which types), alcohol(which actually reduces the pressure), posture.....
I thought some here might find it interesting.

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