Retinal Detachment

Definition

Retinal detachment is the separation of the retina of the eye from its underlying layer of tissue. This separation results in loss of vision. Retinal detachment is a medical emergency.

Description

The retina is a thin layer of light-sensitive cells about the size of a postage stamp located at the back of the eyeball. Underneath the retina lies a layer of cells called the retinal pigment epithelium (RPE). Beneath the RPE is a layer of blood vessels called the choroid. These blood vessels bring nutrients to and remove waste from the RPE. When light strikes the retina, chemical changes occur in the RPE that translate light patterns into nerve impulses. The nerve impulses are transmitted to the brain by the optic nerve, and in the brain they are converted into an image. When the retina is separated from the RPE and the choroid, these chemical changes do not occur and vision is lost.

Demographics

Estimates of the incidence of retinal detachment in the United States vary. Some researchers have found the rate to be between 1 in 10,000 and 1 in 15,000 population. The chance of detachment increases with age; most detachments occur in people between the ages of 45 and 70. Since Americans are living longer, the rate of retinal tears and detachments in the United States is expected to increase. Younger people are most likely to have a retinal detachment because of accidental eye injury.

Causes and symptoms

Causes

Risk factors for retinal detachment include:

• severe nearsightedness
• thinning of the retina at its outside edges (lattice degeneration)
• diabetic retinopathy when abnormal new blood vessels grow around the retina
• participation in contact sports such as football, ice hockey, or boxing
• being hit in the eye with a projectile such as a paintball or baseball
• using pilocarpine drops to treat glaucoma (high pressure in the eye)
• chronic eye infection (uveitis)
• cataract removal when the lens capsule is completely removed and the vitreous gel is disturbed. Complete lens capsule removal has been done infrequently in the United States since 1990, but the procedure accounts for about 30 to 40% of retinal detachments internationally.

There are three types of retinal detachments. Although their causes are different, their signs and symptoms are the same, and all can result in impaired vision. Rhegmatogenous detachments (“rhegma” means to break) occur because a tear in the retina allows fluid to seep between the retina and the RPE.

QUESTIONS TO ASK YOUR DOCTOR

• What type of retinal repair do you plan to do?
• Will I have a gas bubble? How long will it last?
• Will this be an inpatient or outpatient procedure?
• Will I have general or local anesthesia?
• What complications are common for this type of surgery?
• How long will it be before I can go back to work or my daily routine?
• What are my options if this surgery is not successful?
• How many of these operations do you perform each year?
• If my case is complicated, would you consider referring me to a specialized eye hospital for a second opinion or treatment?

The eye is filled with a jelly-like substance called the vitreous gel. The retina tears because as people age, the vitreous gel thickens and shrinks. As it does, it pulls the retina away from the RPE. Shrinking of the vitreous does not always cause a tear, but when it does, fluid can seep between the retina and the RPE, and the retina then peels off the RPE the same way wallpaper peels off a wall where there is a water leak. This is the most common kind of retinal detachment.

Exudative retinal detachments occur when fluid leaks out of the blood vessels in the choroid and accumulates under the retina. There is no tear in the retina, but the retina and the RPE are separated in the same way that the layers of skin are separated in a blister that has not broken. Exudative detachments occur because of inflammatory disease, tumors, or injury to the eye.

Tractional retinal detachments occur because scar tissue on the retina contracts and pulls the retina off the RPE. This is the least common type of retinal detachment.

Symptoms

The classic symptoms of a retinal tear or a retina detachment are flashing lights around the edge of the field of vision and a heavy shower of floaters . The vitreous gel pulling on the retina causes the sensation of flashing light. This pulling does not always cause a tear. Floaters are bits of solid material that have condensed in the vitreous. They look like tiny black specks, although they can also appear as a large cloudy blob in the field of vision. Individuals can have floaters for reasons other than a retinal tear. However, anyone who suddenly sees floaters or flashing lights should see an ophthalmologist immediately.

Once the retina has begun to detach, a sold black spot will appear in the field of vision and grow larger as more and more of the retina detaches. If left untreated, the retina will completely detach and total vision will be lost in that eye.

Diagnosis

A detached retina is usually diagnosed by an ophthalmologist who will refer the patient to a retina specialist. When the eye is dilated, the doctor will use a bright light and magnifying instrument to see if the retina is torn or detached.

Treatment

Some small retinal tears can be treated with cold laser surgery in which tissue around the tear is frozen to tack the retina back on to the underlying tissue. This procedure can be done in a doctor's office. The number, size, location, and cause of the tear determine whether this procedure is appropriate.

Larger tears and detachments require hospital surgery under local or general anesthesia . A retina specialist does this very delicate surgery. Patients may need to stay in the hospital overnight. Three different surgical operations can be performed depending on the specifics of the detachment.

• Pneumatic retinoplexy. This procedure is usually performed on an outpatient basis with the patient under local anesthesia. A laser is used to seal the retinal tear. Gas is then injected into the vitreous cavity. The gas forms a bubble that pushes the retina flat against the back of the eyeball, so that it can reattach. The gas gradually disappears as it is absorbed over a period of several weeks. During this time, the patient may have to keep his or her face parallel to the floor most of the time so that the gas holds the retina in the correct position to encourage reattachment.
• Scleral buckle. This surgery is done in a hospital under local or general anesthesia. The surgeon seals the holes in the retina using either heat or cold or a laser. Next, a small silicon or plastic belt called a scleral buckle is tightened around the outside of the eyeball and sewn into place. This compresses the eye, helps the retina to reattach, and reduces the chance of the vitreous gel pulling the retina away from the underlying tissue in the future.
• Vitrectomy. This procedure is used for large tears, situations in which there is bleeding into the vitreous cavity, abnormal blood vessel growth, scar tissue, and severe infection. In a vitrectomy, the vitreous gel is removed from the eye, retinal tears are sealed and abnormalities corrected through very delicate surgery. Gas is injected into the vitreous cavity and usually a scleral buckle is put in place. The patient keeps his or her head facing the floor for several weeks to keep the gas pressing against the retina until it can reattach. Gradually the gas is reabsorbed and fluid fills the vitreous cavity.

KEY TERMS

Cataract —A condition in which the lens of the eye becomes cloudy and visual acuity is lost. Cataracts can be corrected by outpatient surgery.

Diopter —A unit of measure of the power of a corrective lens. Negative diopter measurements indicate nearsightedness and positive diopter units indicate farsightedness.

Macula —The sensitive center of the retina that is responsible for detailed central vision.

Prognosis

Untreated retinal detachment leads to permanent blindness in the affected eye. About 80% of people experience successful retinal re-attachment after surgery. In some people the retina re-detaches, usually 6 to 8 weeks after surgery, and the surgery must be repeated a second, or even a third, time. Even with successful reattachment there is almost always some loss of vision. The amount of vision lost is directly related to the degree to which the retina detached and the length of time it remained unattached. People whose macula detach almost always lose significant visual acuity.

People who have a gas bubble in the eye often develop a cataract (clouding of the lens of the eye) and may need cataract surgery. New prescription glasses are needed after retinal surgery. Medicare and some insurance policies will pay part or all of the cost for these, since the prescription change is the result of eye surgery. About 15% of people who have a retinal detachment in one eye go on to have detachment in the other eye. Regular eye examinations are essential to detect any changes in either eye.

Prevention

Retinal tears cannot be prevented. Prompt attention to symptoms such as floaters and light flashes in the eye can sometimes prevent a retinal tear from developing into a detachment. Eye safety should be practiced by those participating in sports.

Caregiver concerns

Caregivers should be aware that a retinal detachment is a medical emergency that needs immediate attention. The greater the amount of retina that is detached and the longer it remains unattached, the more likely there will be serious vision loss.

If the patient has a gas bubble in the eye, during the first few weeks caregivers can take on tasks and make adjustments in daily living so that the patient can keep his or her face downward. Correct positioning of the head is important in a successful outcome to surgery. Caregivers should also understand that although vision stabilizes after successful reattachment surgery, visual acuity rarely returns to pre-detachment levels. Depth perception is often affected, and good direct illumination may be necessary for reading to be comfortable.

Resources

BOOKS

Kreissig, Ingrid. Primary Retinal Detachment: Options for Repair. New York: Springer Verlag, 2005.

The Official Patient's Sourcebook on Retinal Detachment: Directory for the Internet Age. San Diego, CA: Icon Health Publications, 2005.

OTHER

“Retinal Detachment.” Mayo Clinic. November 6, 2006 [cited April 1, 2008]. http://www.mayoclinic.com/health/retinal-detachment/DS00254.

“Retinal Detachment.” MedicineNet.com. October 26, 2007 [cited April 1, 2008]. http://www.medicinenet.com/retinal_detachment/article.htm.

“Retinal Detachment.” National Eye Institute. February 2008 [cited April 1, 2008]. http://www.nei.nih.gov/health/retinaldetach/index.asp.

ORGANIZATIONS

EyeCare America Foundation of the American Academy of Ophthalmology, PO Box 429098, San Francisco, CA, 94142-9098, (877) 887-6327, (800) 324-3937, (415) 561-8567, [email protected], http://www.eyecareamerica.org.

National Eye Institute, 2020 Vision Place, Bethesda, MD, 20992-3655, (301) 496-5248, [email protected], http://www.nei.nih.gov.

Tish Davidson A. M.