What is Retinal Detachment?

The retina is a light-sensitive layer of tissue that is located on the inside wall at the back of the eye. The retina is held against the choroid (the outer layer on the inside of the sclera) by the force of the vitreous humour. As we age the vitreous shrinks and changes consistency from its previous elastic state.  A retinal detachment is an uncommon but serious eye condition in which the retina pulls away from its normal position at the back of the eye. As the retina is responsible for sending visual images to the brain via the optic nerve, when a detachment occurs, the vision becomes blurred.  It is most often caused by a related condition called posterior vitreous detachment however it may also be caused by trauma, diabetes or an inflammatory disorder.  During a retinal detachment, bleeding from small retinal blood vessels may cloud the interior of the eye, which is normally filled with vitreous fluid. Central vision becomes severely affected if the macula, the part of the retina responsible for fine vision, becomes detached. Without urgent treatment a retinal detachment can lead to vision loss and eventual blindness.

A retinal detachment is commonly preceded by a posterior vitreous detachment. Commonly observed symptoms include the following:

  • flashes of light (photopsia) - very brief in the peripheral part of vision
  • a sudden dramatic increase in the number of floaters
  • a ring of floaters or hairs just to the side of the central vision
  • a slight feeling of heaviness in the eye

What causes Retinal Detachment?
The vitreous is a clear gel like substance that fills the middle of the eye. It has a consistency of 99% water and the other 1% is made up of fibres that give the vitreous a gelatinous form.  These fibres are mildly attached to the retina. As we age the vitreous changes form and the molecules become less flexible which may result in the vitreous shrinking and pulling away from the retina without causing a problem.  It is when the vitreous pulls hard enough that it pulls on the retina resulting in a retinal tear. There may be numerous retinal tears and it is when the fluid passes through the back of the tear that the retina may start to detach; just like  wallpaper peeling off a wall, it can pull the retina along with it, making a small hole in the retina.  When the retina tears, this allows vitreous fluid to leak behind the retina and further lift it up.  Retinal detachment can occur at any age, but it is more common in the mid to later years.  There are some known risk factors for retinal detachment.  Your ophthalmologist will advise if they recommend you should avoid certain recreational activities that may have an adverse affect in the retina. Cataract surgery is a major cause, and can result in detachment even after an extended period of time after surgery. The increasing rates of cataract surgery, and decreasing age of patients at cataract surgery, will inevitably lead to an increased number of retinal detachments.  Trauma is a less frequent cause. This type of tear can be detected and treated before it develops into a retinal detachment. Retinal detachment does not happen as a result of straining your eyes, bending or heavy lifting.  Although most posterior vitreous detachments do not progress to retinal detachments, those that do, produce the following symptoms:

  • sudden flashes of light in your vision
  • rapid increase of floaters in your vision
  • shadows in the peripheral vision
  • increased feeling of heaviness in your eyes
  • impression of a "veil" or "curtain" over vision and/or
  • loss of the central vision

How is a Retinal Detachment diagnosed?
A retinal detachment can not be seen unless the eye is dilated. Diagnosis can be done by examining the retina in the rooms with the aid of the following instruments:

  • Ophthalmoscope
  • Slit Lamp
  • Ultrasound

Only after careful examination can your ophthalmologist tell whether a retinal rear or early retinal detachment is present.

How can a Retinal Detachment be treated?
Retinal tears will usually need to be treated with laser surgery or cryotherapy (freezing), to seal the retina to the back wall of the eye.  These treatments cause little or no discomfort and will usually prevent progression to a retinal detachment.  In some cases retinal tears are closely monitored without treatment.  Surgery is the only effective treatment for retinal detachment.  Immediate evaluation is critical to determine the best treatment approach. Left untreated, retinal detachment can lead to permanent and severe vision loss.

Types of surgery
Warning signs often appear before retinal detachment occurs, such as the sudden appearance of floaters or sudden flashes of light.  Surgery is ideally performed within a few days of the diagnosis. Prompt treatment is almost always successful in preserving vision.  There are a number of approaches to treating a retinal detachment.  The decision of which type of surgery and anaesthesia to use (local or general), depends upon the characteristics of your detachment.  In each of the following methods, your ophthalmologist will also locate any retinal tears and use laser surgery or cryotherapy to seal the tear.

Pneumatic retinopexy
A gas bubble is injected into the vitreous space inside the eye. The gas bubble pushes the retinal tear closed against the back wall of the eye.  Your ophthalmologist will ask you to maintain a face down head position for several days. As the gas bubble will float, this position will enable the gas bubble to push against the back of the eye and it will gradually disappear.

Scleral buckle
A flexible band (scleral buckle) is placed around the eye to counteract the force pulling the retina out of place.  The ophthalmologist will often drain the fluid under the detached retina from the eye, pulling the retina to its normal position against the back wall of the eye.  This procedure is performed in an operating room.

Vitrectomy may be necessary to remove any vitreous gel which is pulling on the retina.  This may also be necessary if the vitreous is to be replaced with a gas bubble.  Your bodies own fluids will gradually replace this gas bubble, but the vitreous gel does not return.  Sometimes a vitrectomy may be combined with a scleral buckle.  Silicone oil can also be used instead of the gas bubble to keep the retina attached postoperatively.  The silicone will remain in the eye until it is removed (often necessitating a second surgery at a later date).  This technique is advantageous when long term support of the retina is required or for those patients unable to position postoperatively (i.e. children).  Unlike gas, patients are still able to see through clear silicone oil.

After surgery
You can expect some discomfort after surgery.  Your ophthalmologist will prescribe any necessary medications for you and advise you when to resume normal activity.  You will need to wear an eye patch for a short time.  If a gas bubble was placed in the eye, your ophthalmologist will recommend that you keep your head in special position for some time. DO NOT FLY IN AN AIRPLANE OR TRAVEL UP TO HIGH ALTITUDES UNTIL YOU ARE ADVISED BY YOUR OPHTHALMOLOGIST THAT THE GAS BUBBLE HAS GONE!

What are the risks of surgery?
Any surgery has risks; however, an untreated retinal detachment will usually result in permanent severe vision loss or blindness.  Some of these surgical risks include infection; bleeding; high pressure inside the eye; or cataract.  Most retinal detachment surgery is successful, although a second operation is sometimes needed.  If the retina cannot be reattached, the eye will continue to lose sight and ultimately become blind.

Vision may take many months to improve and in some cases may never return fully.  Unfortunately, some patients do not recover any vision.  The more severe the detachment the less vision may return.  Early diagnosis is the key to preventing vision loss associated with retinal detachment.  It is important to get your eyes checked annually and more often if you are at increased risk of eye disease.  For example, in diseases with a high incidence of retinal disease, such as diabetes, routine eye examinations can detect early changes in the eye of which a person might not be aware.  In addition, good control of diabetes can help prevent diabetic eye disease, and blood pressure control can prevent hypertension from damaging the retinal blood vessels.  What happens will depend on the location and extent of the detachment and early treatment.  If the macula has not detached, the results of treatment can be excellent.  It is very important to see your ophthalmologist at the first sign of any trouble.