Difference Between Aqueous Humor and Vitreous Humor

The human eye is composed of six main components, which directly relate to eye optics, namely; cornea, lens, vitreous humor, aqueous humor, and retina.  When we consider the aqueous and vitreous humor, they are the two humors found in the human eye. As their names imply, these two components contain body fluids. However, the aqueous humor is a truly liquid, whereas the vitreous humor is gelatinous mass. Several differences can be found between these two humors. 


What is Aqueous Humor?

Aqueous humor is a clear liquid found in the space between the cornea and the lens. It is constantly generated throughout the entire lifetime by pigmented and non-pigmented epithelium of the ciliary body. The production and drain rate of aqueous humor is about 1 to 2.5 per minute. The maintenance of this rate is vital; otherwise it will increase or decrease the ocular pressure, which eventually leads to many types of glaucoma. In an average individual, aqueous humor contains about 0.2 mL liquid. However, this amount decreases with age due to expansion of the lens.

As the name implies, aqueous humor contains mainly water up to about 98.69%. The rest contains proteins, lipids, coagulation and cell growth inhibitors, electrolytes, glucose, lactase, amino acids, ascorbate, oxygen etc.

Main functions of aqueous humor are nourishing and removing the wastes of avascular structures such as the cornea, the lens, playing a role in refraction of light, and maintaining the intraocular pressure.

What is Vitreous Humor?

Vitreous humor is a clear, gel-like substances present in the rear part of the eyeball, which includes the space between the lens and the retina. This gelatinous mass forms during the embryonic stage and does not replenish with age as it is not served by any blood vessel. Vitreous humor is secreted by non-pigmented ciliary body. It is usually free of microorganism unlike the surrounding tissues because the vitreous humor is enclosed by a series of tough membranes. Even though it is enclosed, it is not an inert part as it contains few cells including phagocytic cells that destroy invading foreign particles and microorganisms.

Vitreous humor is mainly composed of water, which is 98-99% of its total volume. Additionally, it also contains salts, sugars, vitrosin etc.

The main function of vitreous humor is to hold the retina in the eyeball and provide a shape to eyeball.

What is the difference between Aqueous and Vitreous Humor?

• Aqueous humor is a clear liquid found between the cornea and the lens of eye, whereas vitreous humor is a clear gelatinous mass found in the rear part of the eyeball between the lens and retina.

• Aqueous humor is continuously generated and continuously drains from the front of the eye throughout the lifetime, whereas vitreous humor is produced only during the embryonic stage and stays for the entire lifetime.

• Vitreous humor does not replenish while aqueous humor does.

• The volume of vitreous humor is higher than that of aqueous humor in a single eye.