Vitreous Humor of the Eye: Anatomy, Function, & Problems

Today’s topic is all about vitreous humor or vitreous body, its anatomy, function, and various problematic conditions. So, stay connected.

vitreous-humor-body-anatomy-function-problems

Do you know? The vitreous body of the normal eye weighs approx. 4 g and occupies a volume of 4 ml.

What is Vitreous Humor of the Eye?

The vitreous humor (also known as the vitreous body) is a clear, transparent gel that fills the space between your lens and retina. It is composed of 99% water along with sugars, proteins, collagen, and other compounds. This vitreous jelly has a surprisingly firm consistency despite the fact that it is comprised of such a large portion of water.

The term “vitreous” is derived from the Latin word “vitreus” which means “glass-like”, and the word “humor or humour” in Latin means “liquid”.

The vitreous body makes up about 80% of the eyeball’s volume, but it doesn’t have a property of refraction of light. But, the vitreous fluids in your eye should be clear enough for light to easily pass through them for normal visual function.

All of this humor is mostly made of water, as well as a lower amount of collagen, salt, and sugar.

Vitreous humor is a stagnant fluid that has no blood vessels and cannot be regenerated or replenished. But, on contrary, the aqueous humor that fills the anterior chamber of the eye, is continuously formed and drained. However, a similarity between vitreous and aqueous humor is that neither relies on blood vessels to do their jobs.

In general, vitreous humor doesn’t possess any cells, but the crystalline lens in front of the humor is made of tightly packed cells.

Embedded in the surface of the vitreous body are specialized cells, called hyalocytes of Balazs. It is found that these cells contribute to the breakdown and renewal of hyaluronic acid.

The vitreous body is a transparent gel that functions to keep the underlying retina pressed against the choroid.

When people age, the vitreous in their eyes tend to thin and may detach from the retina. This is known as a posterior vitreous detachment, in which vitreous humor separates from the retina.

Posterior vitreous detachment is common among people who are above 65. With floaters as its only visible symptom, it will generally heal itself over time.

The vitreous has many anatomical landmarks. Among them are the hyaloid membrane, Berger’s space, the space of Erggelet, Wieger’s ligament, Cloquet’s canal, and the space of Martegiani.

The Function of Vitreous Humor

The vitreous humor does a few important things inside the eyeball. Firstly, it helps to keep your eye’s spherical shape.

Secondly, the vitreous humor comes into contact with the retina (the light-sensitive tissue at the back of the eye that acts like the film of a camera). The pressure of the vitreous humor helps the retina remain in the correct position.

Other important jobs of the vitreous body are to keep your eye clear and to provide shock absorption.

The vitreous humor is an important part of the eye, enclosing most of it and filling its chamber. This allows the eyeball to have a spherical shape without being fluctuated for the eyelids and the walls to hold up. It also secures contact with the retina, which is located at the back of the eye.

The vitreous body, in addition to maintaining eye shape, also keeps vision sharp by allowing light to focus on the retina. The macula of the retina is where sharp vision occurs.

The vitreous fluid that fills the eye is clear and watery which helps to let more light get to where it needs to go for good vision.

Another intriguing function is that the vitreous fluid helps to dampen any sudden shocks or disturbances to the eye. For instance, it absorbs any shock caused by sudden head movements like shaking or rapid turning of the head.

Vitreous humor also protects the eyes and helps fight against certain injuries. For example, you’ll notice that it absorbs more shock during physical activities, such as running or when someone sustains a head injury. If you’re worried about eye damage, vitreous will help alleviate eye-related problems.

What Happens to Vitreous Humor at Old Age?

As people age, the vitreous liquefies and shrinks. It often turns stringy as well, just like the white of a hard-boiled egg does as it ages.

These stringy objects float around the back of your eye, casting a shadow on the retina. These are called ‘floaters’. You may notice them as specks, strings, or other shapes that you see just out of the corner of your eye.

The movement of these objects within the vitreous body creates a shadow on the retina, called floaters. You may notice them as specks, strings, or other shapes that you see just out of the corner of your eye. They are usually only visible when you look at something bright like a blue sky or shining light.

Vitreous Humor Conditions

With increasing age, several normal to sight-threatening vitreous conditions can develop. Some of these common vitreous conditions are mentioned below.

Posterior Vitreous Detachment

Vitreous adheres to the innermost layer of the eye, or retina with the help of millions of fine fibers (connective tissues). Due to the aging process, the fibers of the connective tissues can’t maintain the firm connection between the retina and the vitreous in old ages (above 65).

The peeling away of the connective tissues between the vitreous body and the wall of the retina is known as vitreous detachment or posterior vitreous detachment (PVD).

Vitreous detachment is common in people of age more than 65 years and most commonly seen in people over 80. Other than age, high myopia, eye injuries, eye inflammation such as uveitis increase the likelihood of vitreous detachment in adult and old people.

The immediate symptom of a vitreous detachment is vitreous floaters that might worsen your vision.

Although posterior vitreous detachment is a normal aging process of the eye, you should see your doctor if you notice sudden blurry vision along with flashes and floaters, as there is more risk of developing retinal tears or detachment in the eyes with vitreous detachment.

Vitreous Degeneration

The eyes of children and adults contain thick and gel-like vitreous humor plump, that occupies the entire vitreous chamber. But, as the eye gets older, the gel-like vitreous humor liquifies and becomes thin, and can’t occupy the entire space of the vitreous chamber.

The thinning of the vitreous gel due to aging is known as vitreous degeneration or vitreous syneresis. Vitreous degeneration is the major causative factor of posterior vitreous detachment.

The degeneration of the vitreous is a normal aging process and doesn’t require treatment, although you might notice floaters or squiggly lines in the vision.

Vitreous Hemorrhage

Although the vitreous body is devoid of blood vessels, vitreous hemorrhage might happen in case of rupture of retinal blood vessels surrounding the vitreous chamber. The diseases that affect the retinal vasculatures, such as diabetic retinopathy, sickle cell anemia, etc., are responsible for vitreous hemorrhage.

These diseases cause abnormal retinal blood vessels growth towards the vitreous humor and rupture of these vessels leads to accumulation of blood in the vitreous cavity, causing blurry vision, increased light sensitivity, and floaters.

If left untreated, the vitreous hemorrhage can cause severe blurry vision and permanent sight loss. So, visit your eye doctor if you notice sudden blurry vision, along with increased floaters and reddish tint of your vision.

Retinal Tears

Vitreous detachment sometimes left a clump of fibers on the retinal tissue which might cause small tears in the retina. As the retinal tear is a major cause of retinal detachment, a sight-threatening medical emergency, it’s mandatory to have an eye checkup to treat the condition.  

A small retinal tear at the peripheral retina doesn’t pose a visual threat, but you need to do regular eye checkups just to make sure, the size of the tear is not increasing. In severe form of tear, laser eye surgery may be necessary to seal the tear and prevent further worsening of the condition.

Retinal Detachment

Retinal detachment is the most serious and sight-threatening eye condition due to abnormalities in the vitreous humor. It happens following retinal tears or due to shrinking away of the vitreous from the retinal wall. The vitreous fluid seeps in through the retinal tear and leads to peeling away of the retina from the supporting layers.

If the detachment occurs at the central retina, there will be a sudden loss of vision with flashes of light or photopsia, whereas the retinal detachment at the peripheral area is accompanied by the symptoms of visual field defect and flashes of light.

Retinal detachment is a medical emergency and it requires surgery (vitrectomy) to treat the condition.

What is Vitrectomy?

Vitrectomy is a surgical procedure applied to treat various problems of the retina and vitreous. During this surgery, the ophthalmologist removes the vitreous gel and replaces it with another solution such as silicon gas or oil.

Any retinal or vitreous anomalies such as retinal detachment, retinal tear, or vitreous hemorrhage that threatens the macula, causing sight loss, require surgical treatment or vitrectomy.

When to See an Eye Specialist?

Make an appointment to see your eye doctor if you start experiencing symptoms for anything related to the vitreous humor, which is the fluid in the back of your eye, especially above the age of fifty. These symptoms could include:

  • The development or sudden increase of eye floaters could be one side effect of inflammation to the vitreous
  • The flashes of light that is created from within the eye and not from an outside source.
  • Your vision is becoming more and more restricted and you can see a dark shadow or curtain closing in on the sides.
  • Sudden change in the clarity of your vision or cloudy vision

A Vitreous and Retina specialist can check the health of your vitreous and retina, with a thorough eye exam. This examination ensures that any complications in the vitreous fluid or retina are caught in order to provide necessary treatments.

In a vitrectomy procedure, ophthalmologists remove the fluid and replace it with a saline solution. This process cleanses the chamber and disposes of any blockages in the vitreous.

A Vitrectomy can be used for people who have eye floaters that obstruct their vision or a hemorrhage of the vitreous humor that is affecting it. This vitrectomy procedure will fix any damage to the vitreous humor and restore clear vision to those patients.

Summary

The vitreous chamber is the largest space inside your eye, containing the most prominent liquid found in your body (the vitreous humor). This condition is present at birth and it changes little for most of your lifetime. It does, however, start to shrink when you get into your fifth decade – which can lead to varying levels of vision impairment e.g. floaters or retinal detachment.


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