When was the last time you had your eye pressure checked? Your doctor will usually check the amount of pressure inside your eye at a routine eye exam. But what exactly does this mean?
Today you’re going to understand what is eye pressure, how much of it is normal, and what is considered dangerously high eye pressure.
So whether you are concerned about your vision or just looking to learn more, I hope you get a lot of value from this post. As always, I will use simple terms. You don’t need to be a doctor to understand these concepts.
What Is Eye Pressure?
Your eyes are filled with a fluid that helps them stay inflated like a ball. Unlike most sports balls that have air inside, your eyes have a fluid called aqueous humor.
If there’s more of this fluid inside the eye, there’s more pressure — meaning the fluid is pushing harder against the “walls” of your eye. If there’s less aqueous humor, the eye deflates and loses its shape, just like a basketball without enough air inside. This concept is what’s called eye pressure, or intraocular pressure (IOP).
There needs to be some pressure in there to keep your eye and its structures in place. It shouldn’t be too little, nor too much. Your eye is constantly working to regulate the amount of fluid that it needs, in order to keep IOP at the right levels.
Just like having high blood pressure and hypertension is not a good thing, having high intraocular pressure is not a good thing either.
You may be wondering “when should I worry about eye pressure.” Here’s the deal:
Normal Eye Pressure Range
Normal eye pressure for adults is between 10 and 21 mmHg (millimeters of mercury), assuming that the thickness of your cornea (front surface of your eye) is average. Your cornea being thicker or thinner impacts your true pressure reading.
Because of this, some forms of eye surgery (like PRK) can cause standard eye pressure readings to appear normal when in fact the true pressure reading is very high.
With that normal range in mind, an IOP reading above 21 mmHg is considered dangerously high eye pressure. Your eye doctor will likely want to follow up with you if you get an IOP reading close to this.
When it comes to how eye pressure affects different people, a paper that reviewed different studies on the distribution of IOP in the general population of countries all around the world concluded that eye pressure increases with age.
As to differences between men and women, some studies report that women have higher mean intraocular pressure. Other studies show no differences between the sexes. However, no study found that men have higher levels of eye pressure than women.
Normal Eye Pressure Range by Age Chart
A study in Pakistan looked at the eye pressure of 8036 healthy subjects to figure out if there’s any correlation between age and IOP. Here’s an overview of the results:
|Age Group (in years)||Mean Eye Pressure (in mmHg)|
As you can see, eye pressure increases progressively with age until you turn 60 years old. Even though the study was only conducted on people from Pakistan, it also concluded that the effect of age on intraocular pressure is similar to what is reported in Western populations, based on previous studies in these regions.
Cool! Now we know what is eye pressure and how much of it is normal. But you may be wondering how do doctors measure it:
Eye Pressure Test
Doctors measure your eye pressure through a procedure called tonometry. All that your doctor is doing when measuring your eye pressure is applying a slight amount of force to the front surface of your eye and measuring how much force is generated back.
The main options your doctor has to gently apply this force to your eye are a tiny special device or a warm puff of air. The way your eye responds to this is an indication of how much pressure it has inside.
During tonometry, eye drops that numb your eyes temporarily (like atropine) may be given to you, so that you don’t feel any discomfort.
Ok! We now know how the measurement of eye pressure works. But what are the symptoms of increased eye pressure? Here’s the deal:
Symptoms of High Eye Pressure
High eye pressure (also called ocular hypertension) often appears without any noticeable symptoms or pain. But it is as dangerous to your eyes as high blood pressure is to your heart.
For this reason, regular eye examinations with an eye care professional are very important to rule out any damage caused by high pressure.
The only time where high eye pressure symptoms may be noticeable is if it’s extremely high pressure (like 35 mmHg or higher). This can cause pain in and around your eye and nausea or vomiting.
How Serious Is Ocular Hypertension?
Ocular hypertension is very dangerous because it’s associated with glaucoma, which is the top cause of blindness today.
Too much fluid inside your eye can push and overload the optic nerve in the back of your eye, causing the damage that leads to glaucoma.
The optic nerve is made up of millions of tiny fibers. As these nerve fibers die due to high eye pressure, you will develop blind spots in your vision. You may not notice these blind spots until it’s too late and most of your optic nerve fibers are dead. If all the fibers die, you will become blind.
Since ocular hypertension doesn’t have symptoms, most people don’t know there’s a problem until it’s too late. For this reason, many people consider glaucoma the silent killer of eye diseases. It’s something that develops so slowly that you won’t know you have it until you basically start to go blind.
You can have glaucoma for years without noticing any changes in your vision. The only way to avoid with is with regular eye examinations.
What Causes High Pressure in The Eye?
If you have high pressure in your eyes, that’s either because your eyes produce too much aqueous humor, or because the fluid is circulating incorrectly and is not being drained, causing it to build up.
Other than an imbalance in production and drainage of aqueous humor, other causes of ocular hypertension include:
- Inflammation of the eye
- Genetic factors (such as a family history of glaucoma)
- Side effects from medications (such as steroids)
- Eye injury or disease
- Having a thin cornea
- High stress
Now that you know how important it is to get your eyes checked, let’s take a look at how doctors can help reduce eye pressure. Here’s the deal:
Eye Pressure Treatment
To treat high intraocular pressure, your eye doctor may prescribe special eye drops to reduce eye pressure. These eye drops work by either lowering the amount of fluid your eye produces or by helping your eye drain the fluid better.
You will need follow-up exams to see if the eye drops are working for you. Your eye doctor will explain everything in detail and keep up with you.
If eye drops don’t work for you, surgery is also an option. Surgery for ocular hypertension works by improving the drainage system and allowing excess aqueous humor to drain from inside the eye.
High eye pressure is not likely to go down on its own unless you address it. Other than eye drops and surgery, you can also try to control high eye pressure and improve your overall eye health through good lifestyle choices:
How Can I Lower My Eye Pressure Naturally?
If you’re wondering “how can I lower my eye pressure without medication or surgery”, here are some recommendations that you can try:
- Exercise and eat healthy. Glaucoma is linked with diabetes and high blood pressure. Eating a healthy diet and staying active and hydrated is not only good for your general health but can also help to reduce high IOP.
- If you use computers for much of the day and start to feel a sensation of pressure or dryness in your eye, blink more to help lubricate the surface of your eyes and give yourself short breaks every 15 to 30 minutes by looking off into the distance. This helps to relax your eye muscles, as they get tired of doing close work all day.
- Practice mindfulness meditation. Studies show that mindfulness mediation can lower intraocular pressure by 25%. This probably happens because high eye pressure is associated with high stress, and meditation reduces stress.
If none of this helps, a visit to your doctor will help rule out any more serious diseases you may have. If you’re already taking medications for glaucoma, don’t replace them with these natural tips before talking with your doctor.
Myopia and High Eye Pressure
Scientists don’t fully understand the relation between myopia and glaucoma yet. But the main theory behind why myopia can lead to glaucoma has to do with the shape of the myopic eye.
If you have myopia, you have an eyeball that is longer than normal. This makes the focal point of light fall in front of the retina and is what causes your distance vision to be blurry. The retina is located in the back of the eye and is responsible for translating light into an image that the brain can read. For clear sharp vision, light needs to fall exactly on top of the retina.
This increased eyeball leads to a “tilting” of the optic nerve in the back of the eye, which is what may cause the damage that leads to glaucoma.
In general, the higher the myopia eye prescription, the earlier the beginning of other complications that threaten your vision.
The Bottom Line
There you have it! Your complete guide to what causes high eye pressure and how to reduce it. Here’s a recap:
The pressure level of your eye depends on how much fluid the eye produces, whether the fluid can travel through the eye, and how well the fluid drains from the eye. Intraocular pressure tends to increase with age.
The normal range of eye pressure is between 10 to 21 mmHg. The higher your eye pressure is, the greater the risk of damage to your optic nerve. This damage can lead to glaucoma.
Regular eye examinations with an eye care professional are very important, as the symptoms of high eye pressure are mostly non-existent.
4 Cited Research Articles
- Colton, T, and F Ederer. “The distribution of intraocular pressures in the general population.” Survey of ophthalmology vol. 25,3 (1980): 123-9. doi:10.1016/0039-6257(80)90086-7
- Qureshi, I A. “Age and intraocular pressure: how are they correlated?.” JPMA. The Journal of the Pakistan Medical Association vol. 45,6 (1995): 150-2.
- Abe, Ricardo Y et al. “Can Psychologic Stress Elevate Intraocular Pressure in Healthy Individuals?.” Ophthalmology. Glaucoma vol. 3,6 (2020): 426-433. doi:10.1016/j.ogla.2020.06.011
- Dada, Tanuj et al. “Mindfulness Meditation Reduces Intraocular Pressure, Lowers Stress Biomarkers and Modulates Gene Expression in Glaucoma: A Randomized Controlled Trial.” Journal of glaucoma vol. 27,12 (2018): 1061-1067. doi:10.1097/IJG.0000000000001088
- Joseph, Dini Sunny, Bindu Thampi, Antony Joosadima, & Ajith Mohan. “A study on association between intraocular pressure and myopia.” International Journal of Research in Medical Sciences [Online], 4.6 (2016): 2202-2205. Web. 30 Mar. 2022
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