The Background

Over the last several years, research has indicated a strong correlation between the presence of Obstructive Sleep Apnea (OSA) and glaucoma. Information from some of these pivotal studies is presented below.

Did you know

• Glaucoma affects over 60 million people worldwide and almost 3 million people in the U.S.
• There are many people who have glaucoma but have not yet had it diagnosed.
• Glaucoma is the second-leading cause of blindness in the U.S. behind macular degeneration.
• If glaucoma is not detected and goes untreated, it will result in peripheral vision loss and eventual, irreversible blindness.

• Sleep apnea is a condition that obstructs breathing during sleep.
• It affects 100 million people around the globe and around 25 million people in the U.S.
• A blocked airway can cause loud snoring, gasping or choking because breathing stops for up to two minutes.
• Poor sleep due to sleep apnea results in morning headaches and chronic daytime sleepiness.

The Studies

In January 2016, a meta-analysis by Liu et. al., reviewed studies that collectively encompassed 2,288,701 individuals over six studies. Review of the data showed that if an individual has OSA there is an increased risk of glaucoma that ranged anywhere from 21% to 450% depending on the study.

Later in 2016, a study by Shinmei et al. measured the intraocular pressure in subjects with OSA while they slept and had episodes of apnea. Somewhat surprisingly they found that when the subjects were demonstrating apnea during sleep, their eye pressures were actually lower during those events than when the events were not happening.

This does not mean there is no correlation between sleep apnea and glaucoma - it just means that an increase in intraocular pressure is not the causal reason for this link. It is much more likely that the correlation is caused by a decrease in the oxygenation level (which happens when you stop breathing) in and around the optic nerve.

In September of 2016, Chaitanya et al. produced an exhaustive review of all the studies done to date regarding a connection between obstructive sleep apnea and glaucoma and came to a similar conclusion. The risk for glaucoma in someone with sleep apnea could be as high as 10 times normal. They also concluded that the mechanism of that increased risk is most likely hypoxia – or oxygen deficiency - to the optic nerve.

The Conclusion

There seems to be a definite correlation of having obstructive sleep apnea and a significantly increased risk of getting glaucoma. That risk could be as high as 10 times the normal rate.

In the end, it would extremely wise if you have been diagnosed with obstructive sleep apnea to have a comprehensive eye exam in order to detect your potential risk for glaucoma.

Article contributed by Dr. Brian Wnorowski, M.D.

This blog provides general information and discussion about eye health and related subjects. The words and other content provided on this blog, and in any linked materials, are not intended and should not be construed as medical advice. If the reader or any other person has a medical concern, he or she should consult with an appropriately licensed physician. The content of this blog cannot be reproduced or duplicated without the express written consent of Eye IQ.

There are several different variations of Glaucoma, but in this article we will mainly focus on Primary Open Angle Glaucoma. This means that there is no specific underlying cause for the Glaucoma like inflammation, trauma or a severe cataract. It also means that the drainage angle where fluid is drained from the inside of the eye into the bloodstream is not narrow or closed.

Closed or Narrow Angle Glaucoma, which will be discussed in another article, is treated differently from Open Angle Glaucoma

In the U.S., Primary Open Angle Glaucoma (POAG) is by far the most common type of Glaucoma we treat.

Glaucoma is a disease where the Optic Nerve in the back of the eye deteriorates over time, and that deterioration has a relationship to the Intraocular Pressure (IOP).  Most - but not all - people diagnosed with Glaucoma have an elevated IOP.  Some people have fairly normal IOP’s but show the characteristic deterioration in the Optic Nerve. Regardless of whether or not the pressure was high initially, our primary treatment is to lower the IOP. We usually are looking to try to get the IOP down by about 25% from the pre-treatment levels.

The two mainstays of initial treatment for POAG in the U.S. are medications or laser treatments. There are other places in the world where Glaucoma is initially treated with surgery. However, while surgery can often lower the pressure to a greater degree than either medications or laser treatments, it comes with a higher rate of complications. Most U.S. eye doctors elect to go with the more conservative approach and utilize either medications - most often in the form of eye drops - or a laser treatment.

Drops

There are several different classes of medications used to treat Glaucoma.

The most common class used are the Prostaglandin Analogues or PGA’s.  The PGA’s available in the U.S. are Xalatan (latanaprost), Travatan (travapost), Lumigan (bimatoprost) and Zioptan (tafluprost).

PGA’s are most doctors’ first line of treatment because they generally lower the IOP better than the other classes; they are reasonably well tolerated by most people; and they are dosed just once a day, while most of the other drugs available have to be used multiple times a day.

The other classes of drugs include beta-blockers that are used once or twice a day; carbonic anhydrase inhibitors (CAI’s ), which come in either a drop or pill form and are used either twice or three times a day; alpha agonists that are used either twice or three times a day; and miotics, which are used three or four times a day. All of these other medications are typically used as either second-line or adjunctive treatment when the PGA’s are not successful in keeping the pressure down as single agents.

There are also several combination drops available in the U.S. that combine two of the second-line agents (Cosopt, Combigan, and Symbrinza).

Laser

The second option as initial treatment is a laser procedure.

The two most common laser treatments for Open Angle Glaucoma are Argon Laser Trabeculoplasty (ALT) or Selective Laser Trabeculoplasty (SLT).  These treatments try and get an area inside the eye called the Trabecular Meshwork - where fluid is drained from the inside of the eye into the venous system - to drain more efficiently.

These treatments tend to lower the pressure to about the same degree as the PGA’s do with over 80% of patients achieving a significant decrease in their eye pressure that lasts at least a year.  Both laser treatments can be repeated if the pressure begins to rise again in the future but the SLT works slightly better as a repeat procedure compared to the ALT.

Article contributed by Dr. Brian Wnorowski, M.D.