Retinal detachment

Many diseases that affect the eye do not lead to blindness, but a retinal detachment that is not repaired can lead to permanent severe loss of vision.

The retina is the innermost layer of the eye. It is responsible for vision and when it is not lying in its normal place, it does not function normally and can slowly die away. The retina detaches from its normal position and moves forward in the eye cavity if a tear is present in the retina, and if there is something pulling on it to bring it forward.

If we understand the eye like a soccer ball, a gel called vitreous occupies the cavity filled with air in a football. The vitreous is normally in contact with the retina, but with normal aging, it liquefies, condenses and separates from the retinal surface. It is during this process that we can see floaters or "flies" moving around in the eye, particularly on bright backgrounds. This is a normal phenomenon, but can be quite bothersome in some people (See section on floaters for more detail).

In some situations, the junction between the vitreous and the retina may be particularly strong. As the vitreous separates, it can pull so hard on the retina that it causes a tear or hole in the retina. As we said earlier this can lead to a detachment when fluid from the vitreous cavity moves into the space under the retina causing what we call a to allow a rhegmatogenous retinal detachment (a detachment caused by a break in the retina).

Some people may be predisposed to retinal detachment by having areas in the peripheral retina that are weaker. To find these areas, an eye specialist has to dilate you pupil (make it very big) so that he can look in with a special lens and light scope. With this he can examine the retina, see tears or detachments, and decide if a special preventative treatment is necessary, or if you have a detachment, indicate to you what the best treatment will be to take care of it.

Nearsighted people are known to be at risk for weaknesses in their peripheral retina. The more nearsighted a person is, the higher the risk of a retinal detachment. Therefore, we usually recommend that nearsighted people get regular eye exams, even if the nearsightedness is corrected with laser (refractive) surgery.

Patients that have had cataract surgery in the past have an increased risk of detachment also. If on an annual basis, 1 per 10 000 people can be expected to have a retinal detachment, this risk increases to 1 per 1000 people after cataract surgery, starting about 2 years after the surgery was done. Other risk factors include past ocular trauma, inflammation or medical conditions such as diabetes.

Not all retinal detachments are just due to a tear in the retina. Some have also traction on the edges of the tear pulling the retina inwards. These so-called tractional detachments are more complicated to repair and are seen in long standing detachments, those associated with ocular inflammation, or retinal neovascularization as can be seen in diabetic retinopathy, retinopathy of prematurity, retinal vein occlusions and uveitis, in particular pars planitis.

What do you experience as a patient?

Signs experienced by patients with a condition affecting the inside of the eye can be quite varied so you have to be careful in interpreting them. Only an eye specialist looking into your eye can confirm a diagnosis of a retinal detachment.

Just before a detachment occurs, a patient often sees lights or flashes in the affected eye. These usually worsen when the lights are turned off as when one goes to bed and usually indicated that something is pulling of the retina.  At about the same time, the patient might experience the presence of abundant floaters.

Once a retinal detachment is present, a shadow or “black curtain” can be seen. It starts at the very periphery of the vision and moves towards the center of vision, as the retina detaches more and more from its normal position. If you have any of these symptoms, it is best to see an eye specialist as soon as possible. If the detachment is small it often can be dealt with without having to perform surgery. If it becomes large, surgery will be required.

What will the eye exam consist of?

The eye specialist will first determine what you are able to see, and check the front part of your eye. He/she will then proceed to dilate your pupil and using a special scope called an indirect ophthalmoscope, he/she will examine your retina to determine how extensive the detachment is, and will try to find the location of the tears in your retina.

He/she is also likely to make a diagram representing the location and size of the detachment as well as the location of all holes and tears. This will help in the planning of next step - the repair of your retinal detachment.

How is a detachment repaired?

Repairing a retinal detachment is a surgical procedure. If it is small, sometimes laser is sufficient to prevent further progression. This can be done in the office using either an indirect ophthalmoscope fitted with a laser, or using a contact lens at a slit lamp. A diode or argon laser can be used for this purpose. An alternative is the use of cryotherapy.

If the detachment is too important, surgery will be required. This is usually carried out under local anesthesia. The surgical approach may involve the external placement of what is called a scleral buckle or scleral sponge, or it may imply the removal of the vitreous gel by means of a pars plana vitrectomy and an intraocular tamponade.

Your eye specialist will explain to you the best surgical approach for the repair of your retinal detachment.

Retinal detachments can be successfully repaired in over 98% of cases, many times with a single operation.