In your usual eye exam, one thing that your eye doctor always checks is your intraocular pressure.
It gives you an important picture of the health of your eye and you can find signs of optic nerve damage that could affect your eyesight.
Your eyes are full of fluid that helps keep them inflated like a ball. The “normal” pressure in the eyes can change during the day and differ from person to person. In healthy eyes, fluids drain freely to maintain constant eye pressure.
If the pressure in your eye is constantly too high or too low, it could be a warning that you may have problems with your vision.
What is considered normal eye pressure?
Normal intraocular pressures average between 12-22 mm Hg. The “mm Hg” refers to millimeters of mercury, which is a scale to record eye pressure.
Eye pressure may vary hourly, daily and weekly. Many factors can affect the up and down changes in a person’s intraocular pressure. These daily changes are normal.
In general, the higher the pressure, the greater the risk to the optic nerve. Some optic nerves develop glaucoma even at low pressures (this is called normal tension glaucoma) so it is important that the optic nerve be examined no matter what the pressure is.
Eye pressure control
A tonometry test measures your intraocular pressure. It’s like pressing a balloon to look for air. It shows how firm your eyeball is with the same units of measurement used to control blood pressure.
The normal range for intraocular pressure is approximately 10-20 mm HG.
The test is done in several ways. Your doctor can touch your eye with the tip of a tool. You may first be given drops to numb the eyes. Rarely, your doctor may give you a puff of air in your eye.
Why eye pressure is important
Normal intraocular pressure helps maintain the shape of the eye, which in turn supports the 2 million parts of the eye that help you see.
Types of pressure:
High pressure : when the fluid in the front of the eye does not drain as well as it should, the pressure may be too high. Your doctor can call this ocular hypertension .
It can cause glaucoma, a group of eye diseases that causes blindness. High eye pressure is one of the main reasons why people suffer from it.
Glaucoma vision loss occurs when the eye pressure is too high for the specific individual and damages the optic nerve. Any resulting damage can not be reversed.
Peripheral (lateral) vision is usually affected first. Changes in vision can be so gradual that they are not noticed until a large loss of vision has already occurred.
There is no specific level of high eye pressure that definitely leads to glaucoma; On the contrary, there is no lower level of intraocular pressure that completely eliminates a person’s risk of developing glaucoma.
That is why early diagnosis and treatment of glaucoma is the key to preventing vision loss.
Glaucoma does not hurt, and you may have it for years without noticing any change in your vision. Therefore, controlling high eye pressure can help you detect it early.
You may have ocular hypertension after an injury or eye disease. Some medications, such as steroids, can also raise the pressure in your eye.
It can also occur after certain medical procedures, such as when a tube is placed in the throat. If yours is already high, a peak can damage your vision.
Low pressure : this is a less common concern than high eye pressure. Often, people suffer from low pressure due to a leak in the eye after surgery.
For some people, very low blood pressure can cause blurred vision or other problems. Others can see well with that.
When the pressure is less than 5 mm HG, doctors call it ocular hypotonia. It can make you more likely to have several eye problems, which include:
- Swelling in the cornea, the clear external dome of his eyes.
- Damage to the macula, the light sensitive part of the retina that allows you to see.
Unlike blood pressure, danger zones for eye pressure can be difficult to pin down. People can have different ranges for what is normal.
One in 3 people with glaucoma never has “high” eye pressure, while others may have a higher than normal pressure without damaging their optic nerves.
That is one of the reasons for you to see an ophthalmologist or other eye care provider regularly.