Description

Retinal detachment (RD) is a disorder of the eye in wich the retina peels away from its underlying layer of support tissue. Initial detachment may be localised,

but without rapid treatment the entire retina may detach, leading to vision loss and blindness. it is a medical emergency.

The Retina

The retina is a thin layer of light sensitive tissue on the back wall of the eye. The optical system of the eye focuses light on the retina much like light is focused on the film in a camera.

The retina translates this focused image into neural impulses and transmits them to the brain via the optic nerve.

The Retina

RD will affect about one out of 10 000 people each year. This is a serious eye problem that may occur at any age, though usually it occurs in middle-aged or older individuals. It is more likely to develop in people who are nearsighted, or whose relatives had retinal detachmenst.

Severe trauma to the eye, such as contusion or a penetrating wound, may be the cause, but in the great majority of cases, retinal detachmentis the result of internal changes in the vitreous fluid associated with aging, or less frequently, with inflammation of the interior of the eye.

There are some retinal detachments that are caused by other diseases, such as tumours, severe inflammations or complications of diabetes. These secondary detachments do not always need surgery, but sometimes improve by treating the underlying cause.

In most cases, retinal detachment develops slowly. The first symptoms is often the sudden appearance of a large number of spots floating loosely in the eye. You may also notice a curious sensation of flashing lights.

Because the retina does not contain sensory nerves that relay the sensation of pain, the condition is painless. Detachment usually begins at the thin peripheral edge of the retina and extends gradually towards the more central areas. The patient perceives a shadow that begins peripherally and grows in size, slowly encroaching on the central vision.

As long as the centre of the retina is unaffected, the vision when the person is looking straight ahead is normal; but when the centre becomes affected, the eyesight is distorted, wavy and indistinct. If the process of the detachment is not halted, total blindness of the eye ultimately results. The condition does not spontaneously resolve itself.

There are several methods for treating a detached retina:

  • If there is a tear, but the retina is not detached it can be sealed with laser therapy and surgery may not be necessary.

    • There are two surgical approaches:

  • Attaching a silicone band externaly around the eyeball. This indents the sclera(wall of the eye) inwards, sealing the tear. The fluid is drained from beneath the retina and gas injected into the eye.
  • Removal of the vitreous fluid and sealing the tear internally. Gas or silicone oil is then injected into the eye.
  • Rhegmatogenous retinal detachment: A rhegmatogenous retinal detachment occurs due to a hole or tear in the retina that allows fluid to pass through the hole and detaches the retina.
  • Exudative, serous or secondary retinal detachment: An exudative retinal detachment occurs due to inflammation, injury or vascular abnormalities that results in fluid accumulating underneath the retina without the presence of a hole, tear, or break.
  • Tractional retinal detachment: A tractional retinal detachment occurs when scar tissue, caused by an injury, inflammation or neovascularisation, pulls the sensory retina from the retinal pigment epithelium.

85% of cases will be successfully treated with one operation with the remaining 15% requiring 2 or more operations. After treatment patients gradually regain their vision over a period of a few weeks, although the visual acuity may not be as good as it was prior to the detachment, particularly if the muacula was involved in the area of the detachment.

However, if left untreated, total blindness could occur in a matter of days.