29 Apr What is the Vitreous?
As a retina specialist, my specialty niche is disease pertaining to the retina and vitreous. The retina is the light sensitive tissue which lines the inside of the eye.
The vitreous is the gel like substance which fills most of the eye in the posterior chamber (that portion of the eye behind the iris and lens).
What Does the Vitreous Do?
The vitreous is critical to embryonic development, that is, it’s part of the development of the eye.
The vitreous should be optically clear. You should not be able to see your own vitreous although your eye doctor should be able to see all of your vitreous!
Once we are born, there is no practical function of the vitreous. Because it is 2-3 times thicker than water, it potentially could “plug” cuts or holes into the eye…kind of like putting a finger in a dike.
Vitreous Causes Retinal Detachments
Many of the diseases I treat as a retina specialist stem from the vitreous. If it weren’t for the vitreous, there would not be a retinal surgical sub-specialty – there wouldn’t be any diseases upon which to operate!
The vitreous causes;
Retinal Tears – the vitreous is adherent to the retina. Forces tugging on the retina can cause a retinal tear. This may happen during a PVD (posterior vitreous detachment) or trauma.
Retinal Detachments – There are two basic types of retinal detachments. The vitreous is implicated in both.
Rhegmatogenous retinal detachment – these are the most common types of retinal detachments emanating from a retinal tear. Fluid migrates through the tear and underneath the retina…causing a retinal detachment.
Certain diseases, such as advance diabetic retinopathy can lead to a “traction” retinal detachment. These detachments occur when sheets of protein/scar tissue grow on the surface of the retina and start to detach the retina by “pulling” or causing traction.
These sheets of protein develop in between the vitreous and retina.
Epiretinal membranes are microscopic types of traction retinal detachments as are macular holes.
Diabetic macular edema improves if a PVD develops or a vitrectomy is performed.
Floaters are a common annoyance and for some impair the vision by causing spots in the vision, glare or blurriness.
What Does this Mean?
This is a vestigial tissue, the vitreous is important in our development. Once born, we don’t really need the vitreous.
A vitrectomy, the core operation performed by a retinal specialist, removes the vitreous and is performed a part of the procedure to fix a variety of the problems noted above.
The vitreous does not need to be replaced – we simply don’t need it. During the operation, artificial saline is pumped into the eye. After the vitrectomy, the artificial saline is replaced by our own.