Anterior Chamber

What is the anterior chamber?

The anterior chamber of your eye is a fluid-filled space right behind your cornea. Your cornea is the clear covering that’s at the front of your eye. The word anterior means front, and the anterior chamber is named after its location at the front of your eye. It holds a clear fluid called aqueous humor. While this small chamber and the clear liquid inside it might not seem all that important, it’s actually a critical structure and plays a key role in your vision.

What does the anterior chamber do?

The structure of your eyes is a key part of how they work, and the anterior chamber is one of the most important structures.

If you’ve ever used a magnifying lens, you know that the distance between what you’re looking at, the lens and your eye all have to be just right to get the sharpest view. It’s the same for your eyes. Your corneas must be the right distance from your lens and retina.

This is why the anterior chamber is so important. The fluid inside the anterior chamber creates internal pressure (intraocular pressure) that keeps your eyeball “inflated.” That’s how the cornea stays at the right distance to do its part in focusing light.

How aqueous humor travels through the anterior chamber

When everything is working as it should, the parts of your eye work together to maintain the right balance of aqueous humor in your anterior chamber. This fluid does more than provide internal pressure so that your eyeball keeps its shape. It also carries oxygen and nutrients, and plays a part in your eye’s immune defenses. The fluid in the anterior chamber contributes to the pressure in your eye. Too much or too little pressure may lead to eye damage.

Here’s how the aqueous humor gets to and leaves your anterior chamber:

• Your ciliary body makes aqueous humor.
• It flows into your posterior chamber. This is a small, fluid-filled space behind your iris.
• The fluid flows through your pupil, which opens to your anterior chamber.
• Most of the aqueous humor exits your anterior chamber through the drainage angle. This is near the outer rim of your anterior chamber, where your iris and the outer wall (sclera) of your eye meet.
• The fluid goes into a drainage network called the trabecular meshwork.

Eventually, the aqueous humor moves into the veins in your sclera where it merges with your blood.

What are the common conditions and disorders that affect the anterior chamber?

Several conditions can affect the anterior chamber of your eye. Those conditions usually do so in one of the following ways:

• They cause high pressure in the anterior chamber.
• They cause low pressure in the anterior chamber.
• They change the size or shape of the anterior chamber.
• They let something into the anterior chamber that doesn’t belong there.

High pressure in the anterior chamber

The pressure inside your anterior chamber needs to be high enough to keep your eye the right shape. But if the pressure gets too high (ocular hypertension), it forces parts of your eye behind the iris backward so they press on your retina and optic nerve. That’s what happens when you have glaucoma, one of the leading causes of blindness worldwide.

Low pressure in the anterior chamber

If the fluid level or fluid pressure in the anterior chamber is too low, your eye can “deflate.” That’s called ocular hypotension or ocular hypotony (“hypo” means “low” and is the opposite of “hyper”). This is a medical emergency because it can cause permanent eye damage and blindness in the affected eye.

Punctures and ruptures from eye injuries can also cause low intraocular pressure if too much fluid leaks out of the anterior chamber. This can also happen with certain types of eye surgeries.

Shape or size differences in the anterior chamber

The depth of your anterior chamber is a key factor in aqueous humor flow. If the chamber isn’t deep enough, it can limit fluid flow. And research links shallower anterior chambers with glaucoma.

Things that don’t belong in the anterior chamber

Sometimes, substances that shouldn't be in the aqueous humor can get into the anterior chamber. When that happens, it can interfere with your sight and affect aqueous humor drainage.

Examples of conditions that involve contaminants (foreign substances or objects) in the aqueous humor or anterior chamber include:

• Pigmentary dispersion syndrome and pigmentary glaucoma
• Endophthalmitis from infections entering the aqueous humor
• Eye cancers like intraocular melanoma
• Inflammation from nearby structures, like with certain subtypes of uveitis, or other inflammatory conditions that involve or affect the aqueous humor

What are some common signs or symptoms of conditions that affect the anterior chamber?

If you have these anterior chamber-related symptoms, you need to get medical attention immediately:

• Blood accumulating/filling up your eye in front of your iris (hyphema)
• Bulging or enlarged eyeballs (buphthalmos)
• Nausea and vomiting that happen with eye pain/pressure
• Rainbow-colored halos around lights
• Sudden vision loss of any kind

There are other anterior chamber conditions that you can have and not experience any symptoms. Or you might not notice anything until your condition gets worse. Symptoms like this include:

• Eye pain or pressure
• Headaches
• Eyes that are red or bloodshot
• Blurred vision
• Gradually developing low vision

What are some common tests that can check the anterior chamber?

Looking at the anterior chamber is a standard part of any eye exam. Several other tests are also possible. They can include:

• Visual acuity test
• Visual field test
• Slit lamp exam
• Tonometry
• Corneal thickness testing (pachymetry)
• Gonioscopy
• Glaucoma-specific tests

Your eye care specialist may recommend other tests, too, depending on your symptoms or if they suspect you might have another eye condition. Your eye specialist can tell you more about the tests they recommend and why these tests might help.

What are some common treatments for anterior chamber conditions?

Because there are so many different types of conditions that can affect your anterior chamber, there are also many possible treatments. A few examples include:

• Medications, especially glaucoma medications
• Eye surgeries, especially glaucoma surgeries
• Treatments for underlying conditions affecting the anterior chamber

Your eye care specialist is the best source of information about possible treatments. They can tailor the information, take your situation and preferences into account, and help you choose.

Can I do anything to care for or protect my anterior chamber health?

There are several things you can do to protect and maintain the health of your eyes, including the anterior chamber. One of the most important things you can do is get regular eye exams. They can detect issues — including anterior chamber conditions — long before you have symptoms. Everyone (not just people who wear glasses or contacts) needs an eye exam every one to two years. And if you have a high risk of conditions like glaucoma, you may need more frequent exams.

Other things you can do include:

• Wearing eye protection. Sports-related eye injuries are a major threat to your eyes. You should also wear eye protection when working with tools, gardening and handling irritating chemicals.
• Managing chronic conditions. If you have conditions that increase your risk of diseases like glaucoma, managing these conditions is extremely important.
• Maintaining your body overall. Your eye health strongly reflects the health of other body systems. Reaching and maintaining a weight that’s healthy for you and getting proper nutrition should be priorities.