The vitreous is a clear gel that fills the back of the eye and is attached to the retina. As we age, this gel becomes fluid-like. This liquefaction may also be caused by previous inflammation inside the eye, nearsightedness, or trauma to the eye. This fluid moves as the eyeball moves and tugs on the retina. With time, the vitreous pulls away and separates from the retina. This is called a posterior vitreous detachment (PVD) and rarely causes a problem.

Flashes and Floaters

Flashes of light are the result of the vitreous tugging on the retina. Floaters are parts of the vitreous that liquefy and pull away from the retina. They may look like spots, circles or strings in the vision. Patients experiencing flashes of light and floaters should be examined immediately to rule out serious retinal problems such as retinal holes, tears, or detachments.

Retinal Tears

Retinal tears may also occur as the vitreous pulls away from the retina. A tear may occur immediately after a PVD or it may happen several weeks afterwards. If the tear occurs over a retinal blood vessel, blood may leak into the vitreous. This is referred to as a vitreous hemorrhage. If there is only slight bleeding, the patient may feel like there are flies in their field of vision. If the bleeding is more severe, the blood may appear as a spider web or like black or red lines swirling in front of their eyes. This may significantly reduce patients’ vision or their vision may become very dark. A retinal tear can be a serious problem. If a hemorrhage is involved it may be even more serious.

Any patient who experiences a sudden onset of floaters or any changes in the floaters they already have, or flashing lights of any type should have a retinal examination immediately to rule out the possibility of a retinal tear. Retinal tears may result in retinal detachment, which can be a serious problem.

Retinal Detachment

When a tear occurs in the retina, the vitreous gel may enter the tear and potentially pull the retina off the back of the eye. Vision loss may occur from a retinal detachment. The signs of a retinal detachment may be a dark shadow or veil coming down from above, below, or from either side. Any patient who experiences sudden flashing lights, new floaters, or loss of peripheral vision should be seen immediately to rule out a retinal detachment.

Retinal tears may be repaired by laser surgery and/or cryotherapy. These procedures are done on an outpatient basis. Laser or cryotherapy may also repair retinal detachments. If the detachment is too large, a scleral buckle may repair it. The physician may also elect to perform a pneumatic retinopexy/cryotherapy. In more complicated cases, the physician may elect to perform a vitrectomy as well.