The aqueous humor and vitreous humor are bodily fluids located in your eyes. While they’re mainly made up of water, they also have other components that nourish and protect your eyes.
One definition of the word “humor” is “a bodily fluid,” and this is true for the fluids found in your eye — the aqueous humor and the vitreous humor.
Your eyes continuously make aqueous humor, the clear fluid in the front part of your eye. The aqueous humor keeps your eye inflated and provides nourishment.
The vitreous humor, also called vitreous fluid, is a clear gel-like substance that’s located in your eye. It takes up the space between your eye’s lens and retina. The vitreous cavity is the name of this space. The vitreous humor helps your eye keep its shape.
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The aqueous humor flows in and out of the front of your eye. Its job is to keep proper ocular pressure (eye pressure) in your eye. The pressure is maintained by having the same amount of fluid come in as the amount of fluid leaving the front of your eye. This fluid fills the anterior and posterior chambers of your eye.
The vitreous humor provides nutrients to your eye and helps your eye keep its shape. It sticks to your retina at the back of your eye and lets light in. Your retina is the part of your eye that communicates with your brain so you can see.
Forensic scientists sometimes use the vitreous humor to find substances in a deceased body that aren’t expected to be there naturally.
Both the aqueous humor and the vitreous humor are parts of your eye.
Your eye has an anterior chamber, which is the area between your lens and cornea. Your eye also has a posterior chamber, which is the area between your lens and iris, which is the colored part of your eye.
In the posterior chamber, the ciliary body makes aqueous humor. That fluid moves through your pupil to the front of your eye and then drains out of your eye into your bloodstream. It leaves your eye through the scleral venous sinus.
The vitreous humor makes up the vitreous body located in the vitreous cavity between your lens and retina of your eye. The vitreous humor is contained in a protective layer called the vitreous membrane. Vitreous humor is more viscous than water but still lets light through. Vitreous humor is responsible for about 80% of the volume of your eye.
Water makes up the majority of both vitreous humor and aqueous humor. Both are about 98% to 99% water.
Vitreous humor also contains salts, sugars, proteins and collagen in addition to water. There are also phagocytes, or cells that help keep your eye clean.
Along with water, aqueous humor also contains amino acids, electrolytes like sodium and potassium, ascorbic acid, glutathione and immunoglobulins.
It’s important to have regular eye exams because finding any kind of condition early is best for treatments and outcomes.
There are several eye conditions that affect or relate to aqueous and vitreous humors, including:
Your ophthalmologist or other provider will ask about your medical history, family medical history and symptoms. These symptoms may include:
Your eye care specialist will look carefully at your eyes during your eye exam. Your provider may use some or all of the following tests:
You’ve probably seen the eye chart before, which has letters on it. The size of the letters keeps getting smaller with every line. Your provider may also have a test using colored dots to see if you can see the difference between colors.
These tests let your provider know how well your eyes move and how far you see to either side of you. Your eye care specialist will move their finger from side to side near your face and may move their finger closer or farther. You’ll only be moving your eyes. Your provider might use a computer for this test.
Your provider will put eye drops in your eyes that make your pupils get bigger (dilate). This makes it easier for them to see all the parts of your eyes. Your provider will use a handheld instrument to look into your eyes. This is called ophthalmoscopy or fundoscopy.
Your provider may also dilate your eyes to do fundus photography or optical coherence tomography to take images of your retinas and optic nerves.
This type of test examines pressure in your eye. An instrument called a tonometer blows a puff of air onto your eye. Your provider may give you eye drops to numb your eyes if there will be contact. There is a method that doesn’t require any contact between the equipment and your eye.
Treatments for eye conditions that involve the aqueous humor or vitreous humor may include:
You can take steps to keep or improve your eye health. This should improve the health of your aqueous humor and vitreous humor. Tips include:
A note from Cleveland Clinic
Eyesight is important to most people. There are things you can do to keep your eyes healthy. This will affect even the parts of your eyes that are fluids: the aqueous humor and the vitreous humor. It’s important to have regular eye exams and report any changes in vision to your eye care provider. As with most types of medical issues, early discovery usually leads to better outcomes.
Last reviewed by a Cleveland Clinic medical professional on 12/27/2022.
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