The vitreous is the clear gel that occupies about 80% of the inside of the eyeball. As we age, this jello-like substance liquefies, shrinks, and eventually separates from the optic nerve and the retina in the back of the eye. This is called posterior vitreous detachment (PVD) and occurs in most adults between 40 and 70 years of age without untoward consequences. A PVD may occur in younger individuals who have undergone cataract surgery or are very nearsighted.
When a PVD occurs, floaters are usually noticed. Floaters are small specks that move in and out of your field of vision. They may be more noticeable when looking at a plain background, such as a white page, wall, or clear sky. Some people mistake floaters for flying bugs. Flashes of light in the periphery of the visual field, particularly in low ambient light, are also a common symptom of a PVD. These flashes are a result of the retina being tugged on by the separating vitreous.
PVD is a common occurrence, which usually has no untoward consequences. However, if the retina is weak or the vitreous gel is abnormal, a retinal tear can occur, which in about 50 percent of cases eventually leads to a retinal detachment.
Being aware of the symptoms of a PVD is the first step to avoiding a retinal detachment. If you begin to notice floaters and flashers, please contact your ophthalmologist for a thorough examination immediately. If detected early enough, retinal breaks can be treated to avoid a retinal detachment.
While early detection is the key, finding a retinal break may be difficult and requires a very thorough examination. Your ophthalmologist will dilate your pupil specifically for this exam and, using a light source and a hand-held lens, will examine the eye as slight pressure is put on the eyeball with a stick-like instrument. This exam will bring any retinal breaks into view and show their exact size and location. In some instances, ultrasonography may be performed to help determine the status of the vitreous and if there are any retinal breaks.
Fortunately, most PVDs do not cause a retinal tear and most treated retinal tears won’t lead to a retinal detachment. However, if a retinal tear is associated with a PVD and not treated with laser, a retinal detachment is likely and further treatment will be necessary.
Floaters may be very distracting initially, but usually become less bothersome over time. In rare cases, floaters can be disabling to the point that removal of the vitreous and floaters by vitrectomy has to be considered.
Occasionally, patients ask about laser for treating disabling floaters. There is no published data demonstrating that using laser to tackle disabling floaters is either safe of effective and we therefore recommend against this treatment.