The human eye is perhaps the most evolved and relied-upon part of the body. From the moment you wake up, you use your eyesight to accomplish most, if not all, of your daily tasks.

Some parts of the eye are widely understood. These include the iris, pupil, lens and cornea. Other features of the eye, however, are unknown. As a result, caring for these lesser-known eye parts may prove difficult, especially if you don’t know where to start.

The vitreous humor and aqueous humor perhaps serve the best example of this. While they are important, few people understand these parts of the eye.

The aqueous humor is a clear fluid located at the front part of the eye. Because the eye doesn’t contain blood vessels, the aqueous humor is responsible for providing nutrients to the eye. The aqueous humor also drains out any excess material and waste from the eye.

The vitreous fluid, or vitreous humor, is a colorless, transparent, gel-like material. Vitreous humor is located between the retina and the lens. It is mainly composed of water with additional levels of protein, salts (electrolytes), sugar (glycosaminoglycan) and collagen.

eye anatomyEye Anatomy

In simple terms, the eye is made up of two parts.

  • Anterior chamber: This is between your iris and cornea; or the "front" part of the eye.
  • Posterior chamber: This is everything behind the lens of the eye filled with a gel-like transparent fluid.

Aqueous Humor

The aqueous humor is what fills up the eye’s anterior and posterior chamber. It is also responsible for your eye’s shape.

Formation of the aqueous humor is correlated with and sensitive to your body’s circadian rhythm. It is a water-like fluid between the cornea and iris.

The aqueous humor’s main job is to:

  • Allow the cornea to expand, so it can protect the eye against dust, particles, and bacteria that can cause harm.
  • Preserve ocular pressure.
  • Transport nutrients, including vitamin C.

The aqueous humor is produced by a part of the eye called the ciliary body, located above the eye’s lens. The aqueous humor must enter and be drained from the eye at an equal rate, exiting the eye from a structure called the trabecular meshwork. This tissue lets fluid drain through it.

Consistent secretion of the aqueous humor is important to your eye’s health.

Maintaining the Health of the Aqueous Humor

Team of happy female soccer players celebrating their achievement on a playing field at sunset.The aqueous humor needs to flow free continuously. Interference with the proper flow can lead to intraocular pressure, which can result in optic nerve damage and vision impairment. Regular eye check-ups can help your doctor detect any issues with the aqueous humor and curate an adequate remedy.

Various lifestyle choices can affect the aqueous humor’s health. The better your health, the more you can reduce the risk of intraocular pressure inside your eye. Some helpful tips:

  • Always wear safety glasses if you’re working in a field that could affect the eye. For example, if you’re a carpenter, or work with a lot of dust, grains, or wind, invest in a good pair of safety glasses.
  • Exercise regularly to relieve eye pressure naturally.
  • Have regular (annual) eye checkups with an optometrist or ophthalmologist.
  • Regulate caffeine intake.
  • Try meditation and relaxation techniques.

Even if you take excellent care of your eye health, increased intraocular pressure is linked with age, conditions like diabetes, a family history of glaucoma, and certain ethnicities.

Vitreous Humor

This is a type of liquid that is also clear. It mostly consists of sugar, salt, collagen, hyaluronic acid, and water.

The main difference between the vitreous humor and the aqueous humor is that there is a set amount of the vitreous humor in your eye, and it does not move  freely about between the two chambers. It remains in the posterior chamber.

In children, the vitreous humor is milky and has a gel-like consistency. The gel-like liquid becomes clearer as you grow older, and in fact begins to liquefy.

Maintaining the Health of the Vitreous Humor

People over the age of 50 may become affected by vitreous detachment as the vitreous humor dwindles. This causes the vitreous humor to change in consistency and become fibrous. Symptoms are:

  • Increased floaters. These are small strands that look like cobwebs or small spots that look like shadows, but they go away once you try to focus on them.
  • Light flashes. You may notice small light flashes in your side (peripheral) vision.

These floaters do not generally result in vision loss, but they can lead to a problems, such as:

  • Retinal detachment. This happens when your retina becomes pulled or lifted from its regular position. It can lead to vision loss if not treated. When there are tears or smaller injuries, this is referred to as a retinal tear. Laser surgery can treat a tear, while traditional surgery may be needed for a retinal detachment.
  • Macular hole. The macula is in the central part of the retina. It is the part of the eye that lets you see things in detail. If a part of your macula breaks, it could result in a hole that causes vision problems. Some macular holes heal on their own, while surgery is needed to repair others. Surgery involves removing the vitreous liquid and supplanting it with a mixture of gas and liquid. You will have to be face down for one to two days or even a few weeks after this surgery. You will usually not be allowed to fly for two months to prevent changes in air pressure from causing the bubble to increase in size, which could result in additional eye pressure.

macular hole diagram

Frequently Asked Questions

  • What does the aqueous humor do?

    A clear fluid at the frontal part of the eye, the aqueous humor provides nutrients to parts of the eye that do not have blood supply. The clear aqueous humor also drains out at an equal rate to remove waste. It makes sure your eye is the right shape and maintains the right amount of pressure in the eye at all times.

  • Why is the vitreous humor important?

    This clear fluid is located between the front part of the eye and the retina. It does not become replenished if some is lost. It plays a more important role in the early years of life, providing structure to the eye and protecting the retina.

    Anything that gets stuck in the vitreous humor must be removed using surgical procedures.

  • What are some ways the aqueous humor and vitreous humor can be damaged?

    The aqueous humor is constantly drained and replenished, but problems with the system that allows the aqueous humor to flow properly can increase intraocular pressure. Increased pressure in the eye can damage your optic nerve and lead to vision loss.

    Glaucoma is often associated with imbalances in the aqueous humor. It means that your eye is either producing excess liquid or that your aqueous humor is not properly able to drain itself through the trabecular network.

    The vitreous humor often becomes stringy as you get older. This may cause small parts to detach and float around your eye. Those who are age 50 or older may also suffer from retinal detachment or macular holes. These must be corrected using surgery.

References

Aqueous Humor. (January 2019). American Academy of Ophthalmology.

Facts About Vitreous Detachment. (August 2009). National Eye Institute.

Aqueous Humor Dynamics: A Review. (September 2010). The Open Ophthalmology Journal.   

How Do We See? (July 2015). Arizona State University School of Life Sciences.

Aqueous Humor Flow and Function. (July 2015). Bright Focus Foundation.

Glaucoma. (November 2018). Mayo Clinic.

Understanding Eye Anatomy – Function of the Vitreous Humor. (October 2017). Eye Pain Management.

The Aqueous Humor. (August 2017). Vision Eye Institute.

Facts About Retinal Detachment. (October 2009). National Eye Institute.

Facts About Macular Hole. (April 2012). National Eye Institute.

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