Retinal Tears & Detachments

The retina is a thin, transparent tissue that lines the back inside wall of the eye. It works like the film of a camera by using its light sensitive receptors to capture images of light that enter the eye. These images are then transmitted to the brain via the optic nerve. Once these electrical impulses have been received by the brain, they are interpreted into sight. Without an intact retina, vision is not possible.

A variety of factors can cause the retina to tear and detach from the back wall of the eye. When detachment occurs, vision can only be saved by immediate medical attention to repair any existing tears and reattach the delicate membrane.

About one in every 13,000 people in North America are affected by retinal detachments every year.

Causes

The back cavity of the eye contains a gel-like substance known as the vitreous. The vitreous fills the cavity in young people, but as a person ages, the vitreous tends to shrink and pull away from the back of the eye. In doing so, it can sometimes pull part of the retina away with it.

This causes the retina to tear, usually in peripheral areas. Once the retina is torn, fluid from the vitreous cavity can seep in through the tear and collect behind the retina, causing it to detach from the wall of the eye. After the retina has started to detach, it will usually continue to do so until most of it has separated from the back of the eye. When the retina is detached, it is no longer sensitive to light and blindness results.

Although the elderly are most likely to experience retinal tears and detachments, other people who are at risk are those who are nearsighted or who have suffered a blow to the eye.

The most common symptoms of retinal tears or detachments are:

• New Floaters: It is normal to have some floaters in the vision, because the vitreous is not completely transparent, but a sudden increase could indicate a retinal problem.
• Flashes: The sudden appearance of flashes in the vision may indicate that the vitreous gel is pulling on the retina and creating traction.
• Shadow or Curtain Over Vision: Retinal detachments are often accompanied by the appearance of a dark, growing shadow, usually in the peripheral (side) vision. The growing shadows occur because the detached portions of the retina are no longer able to respond to light.
• Decreased Vision: A sudden decrease in vision may also indicate a retinal tear or detachment.

The good news about retinal tears and detachments is that most of them can be repaired if medical attention is sought promptly. Anyone who has experienced a retinal detachment should contact an ophthalmologist immediately, or go to the nearest emergency room.

Retinal tears are easier to repair than retinal detachments. They are usually repaired by lasers or a special freezing instrument known as a cryoprobe. These instruments create a scar around the torn area, thereby lessening the chance of a retinal detachment.

Retinal detachments are repaired surgically. The most common method of reattaching the retina is a type of surgery known as a scleral buckle. This procedure involves placing a special band on the eye's outer sclera (the white part of the eye). This pushes the wall of the eye inwards toward the detached retina, facilitating reattachment. The scleral buckle is quite small and is not usually visible after surgery.

Sometimes, in order to reattach the retina, a vitrectomy may be performed. In this surgical procedure, the vitreous is removed from the eye. Air or gas may be injected into the cavity to push the retina back into place. The gases are gradually replaced by the fluid which is produced by the eye.

The amount of vision restored by these procedures depends on such factors as the size and location of the damage, the length of time between the detachment and the reattachment and whether or not a hindering fibrous growth has formed on the retina. Of those people who have retinas reattached, many regain excellent vision, and many others regain much of what they lost. Even if little of the lost vision is restored, the treatment almost always prevents further loss of sight from this type of retinal problem.

After treatment, regular follow-up visits to an ophthalmologist are necessary to ensure that the retina is healing properly. It may take up to one year for the eye to heal completely. Occasionally, a second treatment may be necessary, but the recovery is usually progressive. The eye's focusing ability may change after a scleral buckling surgery, so new corrective lenses may be necessary.