Retinal detachment is a medical emergency requiring prompt surgical treatment to preserve vision.

The retina is the light-sensitive tissue that lines the inside back wall of your eye. In retinal detachment, the retina is pulled away from the underlying choroid — a thin layer of blood vessels that supplies oxygen and nutrients to the retina.

Retinal detachment leaves retinal cells deprived of oxygen. The longer the retina and choroid remain separated, the greater the risk of permanent vision loss in the affected eye.

Fortunately, retinal detachment often has clear warning signs. If you go to an eye specialist (ophthalmologist) as soon as warning signs appear, early diagnosis and treatment of retinal detachment can save your vision.

Retinal detachment is painless, but visual symptoms almost always appear before it occurs. Warning signs of retinal detachment include:

• The sudden appearance of many floaters — small bits of debris in your field of vision that look like spots, hairs or strings and seem to float before your eyes
• Sudden flashes of light in one or both eyes
• A shadow or curtain over a portion of your visual field
• A sudden blur in your vision

When to see a doctor
Seek immediate medical attention if you suddenly notice significantly more floaters or flashes of light in your visual field or if it seems as though a dark curtain has fallen across your vision.

Unfortunately, many people don't appreciate the urgency of the warning signs of retinal detachment, and they tend to put off seeing a doctor in the hope that symptoms will disappear. In some cases, symptoms temporarily diminish only to be followed by a loss of vision over the next few days or weeks, caused by advanced retinal detachment. At this stage, retinal detachment can't always be successfully repaired with surgery, and vision loss may be permanent. So it's best to see your doctor at the earliest signs of retinal detachment.

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Anatomy of the eye

Retinal detachment can occur as a result of:

• Trauma
• Advanced diabetes
• An inflammatory disorder, such as sarcoidosis or cytomegalovirus retinitis
• Sagging or shrinkage of the jelly-like vitreous that fills the inside of your eye

How retinal detachment occurs
Retinal detachment occurs when vitreous liquid (vitreous humor) leaks through a retinal tear and accumulates underneath the retina. Leakage can also occur through tiny holes where the retina has thinned due to aging or other retinal disorders. Less commonly, fluid can leak directly underneath the retina, without a tear or break.

As liquid collects underneath it, the retina can peel away from the underlying layer of blood vessels (choroid). Over time these detached areas may expand, like wallpaper that, once torn, slowly peels off a wall. The areas where the retina is detached lose their blood supply and stop functioning, so you lose vision.

Posterior vitreous detachment
As you age, your vitreous may change in consistency and shrink or become more liquid. Eventually, the vitreous may sag and separate from the surface of the retina — a common condition called posterior vitreous detachment (PVD), or vitreous collapse. This occurs to some extent in most people's eyes as they age.

PVD usually doesn't cause serious problems, but it can cause visual symptoms. If the vitreous pulls on the retina as it shifts and sags, you may see flashes of sparkling lights (photopsia) when your eyes are closed or when you're in a darkened room. The shifting or sagging vitreous may also make new or different floaters appear in your field of vision. These spots, specks, hairs and strings are actually the shadows cast on the retina by small clumps of gel, fibers and cells floating in the vitreous.

If the sagging vitreous pulls too strongly, the retina can tear, leaving what looks like a small, jagged flap. Most retinal tears caused by PVD lead to retinal detachment if left untreated. Detachments that go undetected and untreated can progress and eventually involve the entire retina, causing complete loss of vision in the affected eye.

The following factors increase your risk of retinal detachment:

• Aging — retinal detachment is more common in people older than age 40
• Previous retinal detachment in one eye
• A family history of retinal detachment
• Extreme nearsightedness (myopia)
• Previous eye surgery, such as cataract removal
• Previous severe eye injury or trauma
• Weak areas on the sides (periphery) of your retina

An ophthalmologist may be able to see a retinal hole, tear or detachment by looking at your retina with an ophthalmoscope — an instrument with a bright light and powerful lens that allows your doctor to view the inside of your eyes in great detail and in three dimensions.

If blood in your vitreous cavity blocks the view of your retina, ultrasound examination may be useful. Ultrasonography is a painless test that sends sound waves through your eye to bounce off the retina. The returning sound waves create an image of your retina and other eye structures on a video monitor. This test usually provides the information your doctor needs to determine whether your retina is detached.

Surgery is the only effective therapy for a retinal tear, hole or detachment. Your ophthalmologist can tell you about the various risks and benefits of your treatment options. Together you can determine what treatment is best for you.

If a tear or a hole is treated before detachment develops or if a retinal detachment is treated before the central part of the retina (macula) detaches, you'll probably retain much of your vision.

Surgery for retinal tears
When a retinal tear or hole hasn't yet progressed to detachment, your eye surgeon may suggest an outpatient procedure, which can usually prevent retinal detachment and preserve almost all vision. Healing typically takes about two weeks. Your vision may be blurred briefly following either of these procedures:

• Laser surgery (photocoagulation). During photocoagulation your surgeon directs a laser beam through a contact lens or ophthalmoscope designed for this procedure. The laser makes burns around the retinal tear, and the scarring that results usually "welds" the retina to the underlying tissue. This procedure requires no surgical incision, and it causes less irritation to your eye than does cryopexy.
• Freezing (cryopexy). With cryopexy, your surgeon uses intense cold to freeze the retina around the retinal tear. After a local anesthetic numbs your eye, your surgeon applies a freezing probe to the outer surface of the eye directly over the retinal defect. This freezes the area around the hole, leaving a delicate scar that helps secure the retina to the eye wall. Cryopexy is used for hard-to-reach tears, generally along the retinal periphery. Your eye may be red and swollen for some time after cryopexy.

Surgery for retinal detachment
Doctors commonly use one of three surgical procedures to repair a retinal detachment. If the surgery has a dual purpose — closing retinal holes or tears, in addition to reducing the tug on the retina from a shrinking vitreous — these procedures may be done in conjunction with photocoagulation or cryopexy.

The type, size and location of any retinal detachment will determine which surgical approach your eye surgeon recommends. In general, these surgeries can successfully treat more than 90 percent of cases of retinal detachment, although a second treatment is sometimes necessary.

• Pneumatic retinopexy. For a relatively uncomplicated detachment with the tear located in the upper half of the retina, your ophthalmologist may recommend this outpatient procedure, usually done under local anesthesia. The procedure often starts with cryopexy to treat the retinal tear. Repair of the retinal detachment may require softening the eye by withdrawing a small amount of fluid from the space between the clear dome at the front of your eye (cornea) and the colored part of your eye (iris). Next, your surgeon injects a bubble of expandable gas into the vitreous cavity. Over the next several days, the gas bubble expands, sealing the retinal tear by pushing against it and the detached area that surrounds the tear. With no new fluid passing through the retinal tear, fluid that had previously collected under the retina is absorbed, and the retina is able to reattach itself to the back wall of your eye. The gas eventually disappears after several weeks.

• Scleral buckling. This is one of the most common surgeries for repairing retinal detachment. It's usually done in an operating room under local or general anesthesia. If you have an uncomplicated retinal detachment, this surgery may be done on an outpatient basis.

  First your surgeon treats the retinal tears or holes with cryopexy. Then he or she attaches a small piece of silicone sponge or a firmer piece of silicone rubber to the white of your eye (sclera) over the affected area. The silicone material indents the wall of the eye, creating a buckling effect and reducing traction of the vitreous on the retina. When you have several tears or holes or an extensive detachment, your surgeon may create an encircling scleral buckle around the entire circumference of your eye.

  The scleral buckling material is stitched to the outer surface of the sclera. Before tying the sutures that hold the buckle in place, the surgeon may make a small cut in the sclera and drain any fluid that has collected under the detached retina. The buckle usually remains in place for the rest of your life. Some surgeons may choose a temporary buckle for simple retinal detachments, using a small rubber balloon that's inflated and later removed.

• Vitrectomy. Removing portions of the vitreous itself is occasionally necessary when vitreous clouding blocks the surgeon's view of the detached retina or retinal scarring limits the effectiveness of pneumatic retinopexy or scleral buckling.

  First the surgeon inserts delicate instruments — a light probe, a cutter and an infusion tube — into your eye's interior through tiny incisions in the sclera. Guided by a light from the probe, the surgeon removes scar tissue or opaque areas of vitreous with the cutter, while the infusion tube replaces the volume of removed tissue with a balanced salt solution to maintain the normal pressure and shape of the eye.

  After completing the vitrectomy, your surgeon also may perform a scleral buckling procedure and fill the inside of your eye with air, gas or silicone oil to help seal the retina against the wall of your eye.

Results of surgery
Surgery isn't always successful in reattaching the retina. Also, a reattached retina doesn't guarantee normal vision. How well you see after surgery depends in part on whether the central part of the retina (macula) was affected by the detachment before surgery, and if it was, for how long. Your sight isn't likely to return to normal if the macula was detached.

Your vision may take many months to improve after repair of a complicated retinal detachment. Some people don't recover any lost vision.

Unless you undergo prompt surgery, retinal detachment will cause you to lose vision in the portion of your field of vision that corresponds to the detached part of the retina. Losing part of your vision can greatly change your lifestyle — affecting your ability to drive, read and do many other things you're accustomed to doing. Yet there are ways to cope with impaired vision:

• Check into transportation. Investigate vans and shuttles, volunteer driving networks, or ride shares available in your area for people with impaired vision.
• Get special glasses. Optimize the vision you have with glasses that are specifically prescribed for the effects of retinal detachment. Keep an extra pair of glasses in the car.
• Brighten your home. Have proper light in your home for reading and other activities.
• Make your home safer. Eliminate throw rugs and other tripping hazards within your home.
• Enlist the help of others. Tell friends and family members about your vision problems so that they can help you.
• Talk to others with impaired vision. Take advantage of online networks, support groups and resources for people with impaired vision.

There's no way to prevent retinal detachment. However, being aware of the warning signs of a detached retina — an increased number of floaters, bright flashes of light, or a shadow or curtain that seems to fall across your visual field — could help save your vision. If you notice any of the warning signs of retinal detachment, particularly if you're over age 40, you or a family member has had a detached retina, or you're extremely nearsighted, contact your ophthalmologist immediately.