Retinal detachment is a fairly uncommon occurrence, more likely to occur in individuals over 50 years of age. It is slightly more common in men than women, and in caucasians versus African Americans. Nearsighted patients, whose eyes are bigger than average and who have retinas that are stretched somewhat to fill the eye, also are more likely to have spontaneous retinal detachments. It also has a tendency to run in families.
Causes of Retinal Detachment
Any small opening – a tear or hole – in the delicate retina will permit fluid to get between the retina and the wall of the eye. As the fluid leaks into this space, the retina will slowly peel away from the back wall of the eye. By analogy, think of a thin sheet of wallpaper attached to a wall. If a small hole is made in the paper, and fluid gets through this hole into the area between the wallpaper and the wall, the wallpaper would start to peel off, or detach from the wall onto which it had been glued. What causes small, spontaneous, openings in the retina? Retinal tears may be caused by aging changes in the vitreous gel attached to the retina or degenerative changes in the thin peripheral areas of the retina itself.
The interior portion of the human eye is filled with a gelatinous substance called the vitreous, which helps the globe maintain its shape. When you are a child, the vitreous has the consistency of firm, cold Jell-O (gelatin). Light that is focused by the cornea and lens then passes through the clear vitreous to place an image on the retina, the membranous layer of nerve tissue at the back of the eye. As you get older, the vitreous may start to liquefy a bit and condense. As we approach our 50s, the vitreous gel slowly shrinks and pulls away from its attachments to the retina. If it pulls free completely, the vitreous is said to become separated or detached (a posterior vitreous detachment, or PVD). This is not the same thing as the much more serious retinal detachment.
As the PVD occurs, you may get the sensation of floaters or flashing lights within the eye. These symptoms can be a warning sign that a tear has occurred in the peripheral retina. If these symptoms occur, you should see your eye doctor for an eye examination. Sometimes the process of PVD takes a few weeks to complete itself, so your eye doctor may want to repeat the examination again about one month later. A vitreous detachment does not require treatment as long as there are no retinal holes or tears associated with it.
If your doctor discovers a tear or hole in the retina, it may need to be repaired. By performing the repair, your ophthalmologist is attempting to prevent a retinal detachment from beginning. The type and size of hole, symptoms and condition of the other eye influence whether the retina requires treatment.
In addition to spontaneous occurrence, retinal tears may also appear after trauma to the eye.
Retinal detachment is a serious eye problem affecting 1 out of every 10,000 Americans. Unfortunately, tears and holes in the retina that eventually lead to detachment are part of the aging process. Other risk factors include:
- Extreme near-sightededness.
- A previous detachment.
- A family history of retinal problems.
- A previous cataract surgery.
If you fall into any of these categories, your eye doctor may suggest regular eye exams to catch problems before they lead to limited vision. While retinal detachments primarily afflict middle-aged and older people, detachments can happen at any age.
Retinal neural tissue is very sensitive to any visual or mechanical stimulation. If you sustain a tear in the retina, you may notice several changes:
- You may see an increased number of black spots or floaters in the liquefied vitreous, usually resulting from blood and debris that have entered the vitreous as it pulls away from the retina.
- You may notice a series of light flashes within your visual field, even with the eyelids closed. These flashing lights are the direct result of mechanical stimulation of the retinal neural tissue by the vitreous gel that tugs on it as it separates from the retina.
- Your vision changes after a sharp blow to the eye.
- You may notice a shadow or curtain blocking an area of your vision.
- Typically, you will not experience any pain.
Diagnosis begins with an eye examination for retinal tears and detachment. Several treatment options are available.
If the retina is torn but not fully detached, prompt treatment may prevent further detachment. But if the retina is completely detached, surgery is necessary. This can reattach the retina by sealing the tear to prevent the retina from pulling away from the back of the eye again. Depending upon how severe the detachment is, your eye surgeon may choose from these possible procedures:
If there is only a small amount of fluid around the tear, or a localized detachment, laser treatment may be recommended. The laser seals around the affected area to wall it off and prevent it from spreading.
This freezing technique uses a very cold metallic probe, briefly touched to the outside of the affected area to “freeze” the back wall of the eye behind a retinal tear. Like ophthalmologic laser surgery, this stimulates scar formation, which seals down the edges. Freezing may also be done on an outpatient basis and requires a local anesthetic to numb the eye.
In this procedure, a gas bubble is injected into the vitreous cavity. It floats to reattach the retina. Laser or freezing treatment is preferred to seal the leak.
In the most severe cases – when fluid collected under the retina has completely separated it from the back of the eye – a more complex surgical procedure is required for reattachment. During the procedure, the fluid collected behind the retina may be drained. This allows the retina to settle back into its original position on the eye wall. If necessary, a scleral buckle or silicone “belt” or pressure pad is used to gently push the back wall of the eye against the retina. Then a laser, freeze probe or an electric current applied through a needle (diathermy) seals the retinal tear. More severe detachments may require a vitrectomy, a major procedure in which the surgeon uses delicate instruments – under the guidance of the operating microscope – to remove the vitreous gel away from the retina. This allows the surgeon to complete the reattachment. Eventually the body replaces the removed vitreous fluid.
In this procedure, a silicone belt is placed around the outside of the eye. The belt indents the wall of the eye to gently push the back wall of the eye against the retina. Fluid can be drained from beneath the retina, and freezing treatment applied to seal the leak.
With this operation, tiny holes are made in the wall of the eye to allow access to the center. The vitreous gel is removed from the eye. The retina is flattened under a bubble of air. Laser treatment is applied to seal around the leaks.
More than 90 percent of all detached retinas can now be reattached (although more than one operation may be needed). If successful, the reattachment prevents blindness, and the eye will retain some sight. It takes several months for the eye to seal and reach its final vision, which may vary significantly from the other eye.