by Dan Roberts
The retina is attached to the sclera in the back of the eye, and a retinal detachment occurs when it is pulled away from this normal position. The retina, like film in a camera, is responsible for creating the images that one sees. A good picture could not be produced if the film were not in its correct location within the camera, and we lose vision if the retina is not in its proper place within the eye.
The retina detaches by separating from the back wall of the eye. When it is removed from its blood supply (the choroid), it will lose nourishment and result in a loss of some vision if not repaired in time. This retinal tear may be caused by trauma or by a vitreous detachment (or “posterior vitreous detachment”). Vitreous detachment, not uncommon in older people, results from the vitreous fluid shrinking and pulling away from the retina. This causes “floaters,” which do not damage the retina or vision. However, for a certain percentage of individuals, the vitreous continues to pull away near the torn area and could peel the retina from its normal position in the eye.
The sudden onset of light flashes and floaters could be the warning signs of an impending retinal detachment. They do not always mean that a retinal tear has occurred, but do necessitate a prompt visit with an ophthalmologist. If a retinal tear is discovered before detachment occurs, laser treatment could be performed to possibly prevent separation. Also, a slow enlarging of a dark curtain or shadow in one eye could signify the start of detachment. This curtain usually begins in the peripheral vision, and could move to the central vision. At this point, laser treatment is not helpful, and an operation is usually necessary.
Approximately one out of 10,000 people in the United States develop retinal detachments each year. People who are at highest risk are those with extreme nearsightedness (hypermyopia), a family history of retinal detachment, or thinning of the retina (lattice degeneration) or other degenerative retinal conditions. Such people should have regular retinal examinations and should be alert for symptoms.
Since surgery is the only treatment for an established retinal detachment, there are several procedures which can help. The ultimate goal of each is to repair the tear so that the retina will return to its normal position. The area around the tear is then treated with a laser, creating a strong bond between the retina and choroid and helping to prevent a future detachment.
The surgical procedures currently available are:
Scleral Buckle
This surgery is generally performed in the operating room under general or local anesthesia. The surgeon first treats the retinal tear with cryotherapy by placing a cryoprobe on the outside part of the eye (the sclera) as he looks into the eye. The surgeon then places the cryoprobe in the correct position, and the retinal tear is treated. A piece of silicone elastic plastic or sponge is sewn onto the outer wall of the eyeball (sclera) to create an indentation or buckle effect inside the eye. The buckle is positioned so that it pushes in on the retina, effectively closing the break. This buckle counteracts the forces that are pulling the retina away from it’s normal position, and it is meant to stay in place forever. Another type of scleral buckling surgery can be done with a small rubber balloon, which is removed after a few days.
The silicone may also be placed all around the outside of the eye. Called an encircling scleral buckle or band, this lessens the pulling of the vitreous on the retina. The surgeon may make a tiny slit in the sclera and then puncture the space under the retina to drain the fluid.
There is a better than 80% chance of success with retinal reattachment surgery. The return of good vision, however, depends upon if the macula was detached and for how long. In the best case, it may take many weeks for improvement to be noticed following surgery.
Possible, but infrequent, complications from scleral buckle surgery include failure of the operation, loss of some or all vision, loss of an eye (rare), double vision, retinal hemorrhage, cataract formation, glaucoma, further retinal detachment, proliferative vitreoretinopathy, vitreous hemorrhage, drooping of the upper lid, and infection.
Intraocular Gas Bubble
This procedure involves injecting a gas bubble into the inside of the eye (vitreous cavity). The bubble rises, and holds the retina in place. If the tear can be covered by the bubble, the subretinal fluid will usually resolve within 1-2 days. The main disadvantages are the requirement for precise head positioning for up to 7-10 days following the procedure and a slightly lower initial success rate, as compared to a scleral buckle. The gas bubble is re-absorbed by the body and is not permanent.
Vitrectomy
In more complicated forms of retinal detachments, vitrectomy surgery may be necessary. The vitreous jelly is removed, as well as any scar tissue or blood which may have accumulated. The vitreous is then replaced with special fluid or a gas bubble. For personal accounts, photos, and further descriptions of this procedure, see “Bill’s Vitrectomy,” “Retinal Detachment and Vitrectomy Surgery,” and Vitrectomy Surgery.”
Approximately 90% of common retinal detachments can be initially repaired with one or a combination of these procedures. Improvement of vision in the operated eye could take weeks to months. Blurry vision is to be expected for a period of time. If a gas bubble has been placed in the eye, it will prevent normal focusing until it dissolves. The bubble will dissolve on its own over a period of weeks. If the vision was adequate before surgery, the chances are excellent that good vision will return. If, however, poor vision was evident before surgery, the return of vision will be slow and will probably remain incomplete. It is important to understand that a retinal detachment will almost always result in at least partial blindness if not repaired surgically. If the retina should happen to detach a second time, it will usually occur within several months of surgery, and it can often be repaired with another operation.
There have been great improvements in retinal detachment surgery during recent years, and most patients can be helped if the condition is caught in time.