The vitreous causes most diseases of the retina.
Retinal tears, retinal detachments, macular holes, epiretinal membranes, macular edema, vitreomacular traction, diabetic retinopathy, diabetic macular edema and diabetic retinal detachments are all related to the vitreous.
We suspect even wet macular degeneration may play a role as well, but there is no conclusive evidence.
Even floaters, though not necessarily a disease, can be caused by abnormal optical properties of the vitreous.
Retinal Tears and Retinal Detachments
The vitreous is physically attached to the retina. If you divide the eyeball into a front half and back half while looking straight at the eye, the vitreous and retina are most adherent in the front half.
A PVD, or posterior vitreous detachment, means that the watery gel has separated from the retina in the back half of the eye, or, the “posterior vitreous.”
The anterior half remains adherent to the retina.
Hence, if enough force is generated through the vitreous and pulls on the retina, a retinal tear develops and is almost always in the front of the eye.
Retinal tears can cause retinal detachments. This is why I often recommend a vitrectomy in patients with multiple tears. By removing the vitreous, I am removing the causative agent.
Epiretinal Membranes and Macular Holes
In most cases of epiretinal membranes, a PVD has occurred. In most cases of macular holes, a posterior vitreous detachment has not occurred.
Swelling of the macula from various causes, but including diabetic retinopathy, usually occurs before a PVD occurs, that is, the vitreous is still adherent to the macular region.
What Does this Mean?
In many cases, a posterior vitreous detachment can be dangerous, as in the case of a retinal detachment or retinal tear.
In many more cases, a PVD might be “therapeutic.”
There is no conclusive proof, but separation of the vitreous interface can sometimes prevent macular edema, is probably going to be shown to reduce diabetic macular edema, may prevent retinal detachment from proliferative disease and may prevent two other conditions called vitreomacular traction (VMT) and macular holes.
Presently, a posterior vitreous detachment is a purely natural event, that is, it happens to everyone. Surgically, a posterior vitreous detachment can be induced, or caused, at the time of vitrectomy surgery. This can be a risky part of the procedure as inadvertent retinal tears may develop.
In theory, however, many of the aforementioned conditions might be avoided altogether or at least improved…leading to better vision or preventing further loss.
On the horizon, an enzyme, given as an injection that might chemically cause a PVD.