What is the Vitreous Body?
The vitreous body or vitreous humor is the clear, gelatinous extracellular matrix (ECM) structure that fills the posterior part of the eye. It is made of 40 ECMs and a list of non-ECM proteins, such as albumin, transferrin, and vitellogenin. The vitreous matrix is maintained with little changes throughout life. The gel of the vitreous body does undergo an age-dependent liquefaction which is a continuous loss of collagen IX and collagen II fibrils. The matrix network does not regenerate after vitrectomy.
Key Takeaways
- The vitreous body is a colorless, gelatinous material that fills the back of the eye.
- It provides nutrients, coordinates eye growth, and supports the retina.
- Vitreous detachments, vitreous hemorrhages, and syneresis can affect vision.
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Understanding Vitreous Body
The vitreous body is a transparent, gel-like mass whose main component is water. It plays a role in providing nutrients to the lens, coordinates eye growth and provides support to the retina. It is located close to the retina and may be affected by retinal changes.
Conditions Affecting the Vitreous Body
Vitreous hemorrhages, detachments, and syneresis may affect the vitreous body and decrease one’s vision clarity.
Vitreous Hemorrhage
A spontaneous vitreous hemorrhage can be serious and has a prevalence of 7 per 100,000 people per year. A vitreous hemorrhage is a bleed in the vitreous caused by pathologic mechanisms that disrupt normal retinal vessels, bleeding from diseased retinal vessels and abnormal new vessels, or extension of a hemorrhage through the retina. A hemorrhage into the vitreous body results in rapid clot formation and is followed by slow clearance of approximately 1% per day. A posterior vitreous hemorrhage may be the result of a retinal tear, diabetic retinopathy, vascular proliferation after retinal vein occlusion, age-related macular degeneration or Terson’s syndrome.
Posterior Vitreous Detachment
Posterior vitreous detachment (PVD) is defined as the separation of the posterior vitreous cortex from the inner limiting membrane of the retina. It is commonly associated with aging. A PVD results from the vitreous gel becoming more liquid, which can place traction on the peripheral retina, resulting in rhegmatogenous detachments, pulling on the macula, optic disc, retinal blood vessels, and the creation of premacular membranes that contribute to macular pucker and holes. Posterior vitreous detachment is estimated to occur in two-thirds of those older than 65 years.
Vitreous Syneresis
Syneresis is the liquefaction of the vitreous body which may lead to a floater or PVD. The contraction occurs with age, but may occur with trauma or injury.
Symptoms of the Vitreous Body
An increase in the number of floaters and flashes of light may indicate changes in the vitreous body. Flashes and floaters can be symptoms of a retinal detachment and should be checked immediately by an eye doctor.
Diagnosing Disorders of the Vitreous Body
A doctor may view changes to the vitreous during a dilated fundus examination. Fundus photography may pick up large changes to the vitreous body.
Vitreous Body Treatments
There are no treatments for changes in the vitreous humor resulting in floaters. A vitrectomy may be performed for a vitreous hemorrhage that does not clear and impedes vision. A vitrectomy is rarely performed for floaters resulting from posterior vitreous detachment or syneresis.
