Retinal detachment is a medical emergency requiring immediate surgical treatment to preserve the vision.
The retina is the light sensitive tissue lining the inside of the rear wall of the eye. In the retinal detachment, it is separated from the underlying choroid - a thin layer of blood vessels - which supplies oxygen and nutrients to the retina.
The retinal detachment causes the cells of the retina to be deprived of oxygen. The longer the retina and choroid remain separated, the greater is the risk of permanent loss of vision in the affected eye.
Fortunately, the detachment of retina, often, has clear signs of alarm. If you go the ophthalmologist as soon as these signs of alarm appear, the premature diagnosis and the early treatment, will turn into in an important visual recovery.
Symptoms
Retinal detachment is painless; however visual symptoms usually appear before it happens. Warning signs of retinal detachment include:
- The sudden apparition of floaters – small pieces of vitreous in your field of vision – that are seen like spots, hairs or chains and they seem to be floating in front of your eyes.
- Sudden sparkles of light in one or both eyes.
- A shadow or a curtain covering part of the visual field.
- A sudden cloudiness in your vision
When to consult a doctor
Seek immediate medical attention if floaters or light flashes appear in your field of vision, or if you see a dark curtain on your vision.
Unfortunately, many people do not understand the urgency of the warning signs and symptoms of retinal detachment, and tend to postpone the consultation in the hope that the symptoms will disappear by themselves. In some cases, the symptoms diminish temporarily only to be followed by a complete loss of vision in the coming days or weeks, caused by the total detachment of the retina. At this stage, retinal detachment may not always be successfully repaired by surgery and vision loss may be permanent. Do not doubt to consult the ophthalmologist at the first warning signs of retinal detachment.
Causes
Retinal detachment can occur as a result of:
- Traumatisms
- Advanced Phases of diabetes
- Inflammatory disorders
- Contraction of the vitreous (jelly-like substance that fills the inside of the eye).This is the most common cause of retinal detachment.
How is retinal detachment produced?
Retinal detachment occurs when the vitreous liquid (vitreous humor) is filtered through a retinal tear and accumulates under the retina. Leaks can also occur through tiny holes where the retina has become thin due to age or other diseases of the retinal periphery. With less frequency, the fluid can seep directly under the retina, without an apparent rupture.
When fluid accumulates underneath the retina, it is separated from the underlying layer containing blood vessels that nourishes it (the choroid). Without treatment these separated areas could expand and provoke the retinal detachment. The areas where the retina is separated lose their blood supply and stop functioning, resulting in loss of vision.
Posterior vitreous detachment
As you grow older, the vitreous changes its consistency and becomes more liquid. At any time, it can detach and separate itself from the retinal surface, a common condition, called posterior vitreous detachment (PVD) or vitreous collapse. This occurs to the eyes of the majority of people as they age.
Generally it does not cause serious problems, but it can provoke annoying visual symptoms (floaters). If the moving vitreous pulls the retina, you may see flashes of bright light (photopsias) when your eyes are closed or in a dark room. The displacement or collapse of the vitreous can also generate new floaters that appear in various forms in the field of vision. These spots, hairs or strings that you see are actually the shadows of small lumps of gel, fibers and cells floating in the vitreous projected on the retina.
If the collapsed vitreous pulls too hard, the retina may tear, leaving a small and irregular hole. Most retinal tears caused by PVD lead to retinal detachment if not treated on time. Some that are neither detected nor treated could progress and eventually produce a detachment of the whole retina, causing total loss of vision in the affected eye.
Risk factors
The following factors increase the risk of retinal detachment:
- Age: retinal detachment is more common in people over 40.
- Precedent of retinal detachment in the contra lateral eye.
- Familiar precedent of retinal detachment.
- Extreme myopia.
- Previous eye surgery.
- Prior injury or severe ocular trauma.
- Weak areas on the retinal periphery.
Diagnosis
The specialist is capable to detect a retinal hole, a tear or detachment when examining the eye with an ophthalmoscope - an instrument with a brilliant light and powerful lenses - which allows the doctor to see the interior of your eyes with great details and in three dimensions.
Some pathologies produce hemorrhages in the vitreous cavity (inside the eye) that hinders the correct visualization of the retinal periphery; in these patients echography (ultrasound scan) could be helpful. The echography is a painless examination that sends sound waves through your eye to bounce off the retina. The returning sound waves create a 2D image of your retina and other eye structures on a video monitor. This test provides the information that your doctor needs to determine if the retina is detached.
Treatment
Surgery is the only effective treatment for a tear, a hole or a retinal detachment. The ophthalmologist can inform you about the various risks and benefits of different treatment options. Together with the doctor, you can determine what treatment is right for you.
If a tear or a hole is treated before detachment occurs or if it develops without involving the central part of the retina (macula) it is probable to retain a great part of the original vision after treatment.
Surgery for retinal tear
- When a retinal tear or a hole has not yet progressed to a detachment, retinal ophthalmologist may suggest an outpatient procedure, which normally prevents the detachment of the retina and preserve the vision in most cases. The healing usually lasts about two to three weeks. Your vision may become blurry at first few days, getting back to normal in a few days.
- Laser surgery (photocoagulation). During the photocoagulation a laser beam is directed through a lens of contact or ophthalmoscope, designed for this procedure, toward the affected area of the retina. The laser surgery is used to “weld” the damaged portion of the retina back in place, producing some burns around the retinal tear or holes, and, later, a scar. This procedure requires no surgical incision and causes less eye irritation than cryopexy (a freezing technique).
- Freezing (cryopexy). With cryopexy, the surgeon uses intense cold produced by a device designed for such purpose that achieves freezing the retina around the retinal tear adhering it to the underlying tissue. After a local anesthesia, the 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 bonding the retina to the inner wall of the eye. Cryopexy is used when it is difficult to visualize very peripheral tears that can not be treated with laser. The eye can remain swollen and red for a few days after treatment.
The retinal detachment surgery
The retinologists can use any of the multiple surgical procedures to repair a detached retina. And if the surgery has a twofold purpose – to close retinal holes or tears and to reduce the pulling of the retina by a vitreous contraction – these procedures can be performed in conjunction with photocoagulation or cryopexy.
The type, size and location of any retinal detachment will determine which surgical approach will be recommended. Generally, these surgeries can be successfully treated in more than 80 percent of the cases, although a second treatment is sometimes necessary. Let’s see some of the procedures:
Pneumatic retinopexy. For a relatively simple detachment with tear located
in the upper half of the retina, the ophthalmologist may recommend this outpatient procedure which is usually performed under local anesthesia. The procedure often begins with cryopexy or laser in order to treat retinal tear.
In order to soften the eye, a small amount of liquid between cornea and the iris is extracted. Thereinafter, the surgeon injects an expandable gas bubble in the vitreous cavity. In the two subsequent days, the gas bubble expands almost twice the size, pushing the retina against the interior wall and plugging the tear. The
subretinal fluid passes toward the vitreous cavity permitting the correct application of the retina. The gas is reabsorbed after a couple of weeks.
Conventional scleral surgery. This is one of the most common surgeries to repair a detached retina. Usually it’s done in the operating room under local or general anesthesia. If you have a retinal detachment without complications, this surgery can be performed as an outpatient basis.
First, the surgeon treats the retinal tears or holes with cryopexy as mentioned above. Then, a small piece of silicone sponge or a piece of silicone rubber is placed in the white of the eye (sclera) over the affected area. These explants create an effect of sagging and reduce vitreous traction on the retina. When there are several holes or tears, or detachment is larger, the surgeon may place a scleral belt around the entire perimeter of the eye.
The scleral explant is stitched to the external scleral surface. In order to drain the fluid under the detached retina, the surgeon can make a small incision. The scleral explant is not removed.
Vitrectomy. Total o partial vitreous extraction when it is not clear (condition that prevents the retinal visualization that is necessary to perform cryopexy or scleral surgery) or when it is pulling the retina.
First, the surgeon introduces devices (light, cutter, infusion cannula) inside the eye by small scleral incisions. Guided by the probe light, scar tissue and hemorrhages are eliminated with the cutter, while the infusion flue replaces the extracted volume with balanced salt solution to keep the ocular tension and shape.
After vitrectomy, sclera surgery can be performed and the eye can be filled with air, gas or silicon oil to help the retinal sealed.
Results of surgery
Surgery is not always successful in reattaching the retina on its place, so it could be necessary to do more than one surgery. Besides, an attached retina does not guarantee a normal vision. The visual acuity recovery depends largely on whether the central part of the retina (macula) was involved -or not - before surgery, and if it was, for how long. It is probable that the vision may not be the same if the macula was detached.
The vision may take many months to improve after the repair of complicated retinal detachment. Some people do not recover completely. All the retinal detachment surgeries are emergencies, since as time elapses, it is vital for the prediction of both the anatomical and visual success.
Prevention
There is no way to prevent retinal detachment. However, being conscious of the warning signs of a retinal detachment - increase of floaters, flashes of light, a shadow or a thin membrane that seems to fall through the field of vision –could be helpful. If you notice any of the signs and symptoms of retinal detachment, especially if you are over 40 years old, have had a stroke, present retinal pathology antecedent or high myopia, contact your ophthalmologist immediately.
