INSUFFICIENT SLEEP APPEARS TO BE ASSOCIATED WITH GLAUCOMA, a leading cause of blindness. That is the conclusion of researchers examining more than 400,000 individuals.
Glaucoma is a group of optic nerve-damaging eye conditions. The optic nerve transmits visual information from your eye to the brain. Optic nerve damage is often associated with high pressure in the eye (as is often the case with glaucoma). Still, glaucoma can occur even if you have normal eye pressure.
While glaucoma can occur at any age, it is more common among older adults. The disease is a leading cause of blindness for people over age 60.
Today we explore a United Kingdom study that explores the relationship between insufficient sleep and glaucoma risk.
Glaucoma worsens over time and tends to run in families. Glaucoma can lead to permanent vision loss or blindness within a few years if the damage worsens.
Most individuals have no early symptoms (such as pain or visual loss). By regularly visiting your eye doctor, you are more likely to diagnose and manage glaucoma before you have a long-term visual loss.
Once the vision is lost, you cannot recover it. However, lowering eye pressure may help you keep the vision you have. Fortunately, most individuals with glaucoma who are diligent about regular eye examinations and follow their treatment plan will retain their vision.
Normally, our eye’s fluid (or aqueous humor) flows out of the eye through a mesh-like channel. The fluid can build up if the channel is blocked (or if the eye produces too much fluid). Unfortunately, we don’t know the cause of the blockage, but one can inherit risk.
Less common causes of glaucoma include:
- Eye injury (such as from a chemical or blunt trauma; uncommonly from eye surgery for another condition)
- Eye infection, severe
- Blood vessel blockage in the eye
- Inflammatory conditions
- Steroid medicines
Glaucoma typically affects both eyes but may be worse in one than the other.
According to WebMD, there are two main forms of the condition: open-angle and angle-closure glaucoma. Open-angle (wide-angle) glaucoma is the most common type. The eye’s drain structure (trabecular meshwork) looks normal, but the fluid doesn’t flow out as it should.
With acute or chronic angle-closure (narrow-angle) glaucoma, the eye doesn’t drain properly because the drainage space between your iris and cornea is too narrow. The result? A sudden buildup of pressure within the eye. Angle-closure glaucoma is associated with cataracts and farsightedness.
Less common types include normal-tension glaucoma, a condition with visual blind spots. Alternatively, the optic nerve is damaged, even though the intraocular pressure is normal. Some view it as a form of open-angle glaucoma.
Finally, pigmentary glaucoma involves very small pigment pieces from your iris (the colored portion of your eye) getting into the eye fluid and clogging the drainage canals.
Glaucoma risk factors
While glaucoma most commonly affects adults over 40, one can suffer from the disease at any age. African-Americans are more likely to suffer from the condition at a younger age and with more vision loss.
After cataracts, glaucoma is the leading cause of blindness in African Americans. The Glaucoma Research Foundation explains that many people are unaware that:
Glaucoma strikes earlier and progresses faster in African Americans. The glaucoma risk is 1.2-times higher if the condition runs in the family. Other factors putting African Americans at even greater risk include age over 40, extreme nearsightedness, high blood pressure, diabetes, and prolonged steroid use.
Glaucoma is five times more common among African Americans. Glaucoma-related blindness is roughly six times more common. Glaucoma often occurs at an earlier age in African Americans — on average, about ten years earlier than in other ethnic populations.
We don’t know why African Americans have a higher risk, but inherited genetics plays a role.
Other glaucoma risk factors include:
- African American, Russian, Irish, Japanese, Hispanic, Scandanavian, or Inuit ancestry
- Age over 40
- A family history of glaucoma
- You are nearsighted or farsighted.
- Poor vision
- Steroid medications such as prednisone
- Certain bladder control or seizure drugs. Select over-the-counter cold medicines may raise the risk.
- Eye injury
- Corneas that are thinner than usual
- Hypertension, heart disease, diabetes, or sickle cell anemia
- High eye pressure
Glaucoma symptoms and diagnosis
Most individuals who have open-angle glaucoma do not have symptoms (unless the disease is late in its progression). The primary symptom is a loss of peripheral (side) vision.
Angle-closure glaucoma symptoms typically come on more rapidly and are more apparent. Because damage can quickly occur, if you have any of the following symptoms, please seek medical care: Visual loss; seeing halos around lights; eye redness; eye pain; an upset stomach or vomiting; a hazy-appearing eye (especially in infants).
Many have glaucoma and don’t know it. Regular eye exams are critical to catching glaucoma or other eye problems. Clinicians may perform a dilated eye exam to widen pupils and view the optic nerve at the back of the eyes.
Genioscopy involves an examination of the angle where the cornea and the iris meet. An ocular pressure test (tonometry) measures eye pressure, while optical coherence tomography (OCT) searches for changes in the optic nerve.
Other approaches include pachymetry to measure corneal thickness and a visual acuity test (eye chart) to look for vision loss. A slit lamp exam examines the inside of your eye with a special microscope known as a slit lamp. Finally, a visual field test (perimetry) looks for peripheral vision changes.
Sleep insufficiency and glaucoma
A new research study illustrates an association between poor sleep and glaucoma. The study drew on a database of over 400,000 individuals (in the UK Biobank) to explore links between sleep and vision loss.
The study looked at sleep behavior, including too much, too little, insomnia, daytime sleepiness, snoring, and being a “morning lark” or “night owl.” The study defined normal sleep duration as seven to nine hours. After tracking the health and lifespan of the participants until the first diagnosis of glaucoma, death, emigration, or end of monitoring in 2021, researchers identified 8,690 glaucoma cases.
Here are the results:
Frequent daytime sleepiness was associated with a 1.2-fold higher risk for glaucoma. The risk rose 1.12-times with insomnia and 1.08-times with short or long sleep duration. Snoring was associated with a 1.04-fold higher risk.
Compared with those without glaucoma, participants with the condition tended to be male and older, and have high blood pressure, diabetes, or smoking history.
The risk increases associated with insufficient sleep appear to be relatively small. In addition, the researchers do not establish causality.
The researchers note that glaucoma might influence sleep patterns rather than vice versa. They also offer some possible biological explanations for the association. The internal pressure of the eye rises when we lie down or when sleep hormones are off (as happens with insomnia).
Furthermore, anxiety and depression (sometimes associated with insomnia) may increase eye pressure, possibly due to dysregulated cortisol stress hormone production.
Alternatively, repeated episodes of low oxygen secondary to sleep apnea may also damage the optic nerve.
I want to use this new research as a springboard to talking about glaucoma. Here are some steps from the Mayo Clinic that may allow you to detect and manage glaucoma early, hopefully preventing visual loss (or slowing its pace).
- Get regular eye examinations. Generally, the American Academy of Ophthalmology suggests an eye exam every five to 10 years if you are under age 40; every two to four years if you are 40 to 54; every one to three years if you are 55 to 64, and every year or two if you’re older than 65.
- You’ll need more frequent screening if you have a higher risk of glaucoma. Ask your healthcare provider to guide you to an appropriate screening program.
- Know your family’s eye health history. Glaucoma tends to run in families.
- Wear eye protection. Serious eye injuries can cause glaucoma. Please wear appropriate eye protection when you play sports or use power tools.
- Take prescribed eye drops regularly, as directed (even if you have no symptoms).
Finally, don’t smoke, and watch your caffeine intake. The latter can increase your eye pressure. Elevate your head when you sleep, for example, with a wedge pillow to lower eye pressure.
Glaucoma is a condition that damages your eye’s optic nerve. It gets worse over time. It’s often linked to a buildup of…
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