The retina is the light-sensitive tissue lining the back of our eye. Light rays are focused onto the retina through our cornea, pupil and lens. The retina converts the light rays into impulses that travel through the optic nerve to our brain, where they are interpreted as the images we see. A healthy, intact retina is key to clear vision.
The middle of our eye is filled with a clear gel called vitreous (vi-tree-us) that is attached to the retina. Sometimes tiny clumps of gel or cells inside the vitreous will cast shadows on the retina, and you may sometimes see small dots, specks, strings or clouds moving in your field of vision. These are called floaters. You can often see them when looking at a plain, light background, like a blank wall or blue sky.
As we get older, the vitreous may shrink and pull on the retina. When this happens, you may notice what look like flashing lights, lightning streaks or the sensation of seeing “stars.” These are called flashes.
Usually, the vitreous moves away from the retina without causing problems. But sometimes the vitreous pulls hard enough to tear the retina in one or more places. Fluid may pass through a retinal tear, lifting the retina off the back of the eye — much as wallpaper can peel off a wall. When the retina is pulled away from the back of the eye like this, it is called a retinal detachment.
The retina does not work when it is detached and vision becomes blurry. A retinal detachment is a very serious problem that almost always causes blindness unless it is treated with detached retina surgery.
Vitreous gel, the clear material that fills the eyeball, is attached to the retina in the back of the eye. As we get older, the vitreous may change shape, pulling away from the retina. If the vitreous pulls a piece of the retina with it, it causes a retinal tear. Once a retinal tear occurs, vitreous fluid may seep through and lift the retina off the back wall of the eye, causing the retina to detach or pull away.
Vitreous fluid normally shrinks as we age, and this usually doesn’t cause damage to the retina. However, inflammation (swelling) or nearsightedness (myopia) may cause the vitreous to pull away and result in retinal detachment.
People with the following conditions have an increased risk for retinal detachment:
• Previous cataract, glaucoma or other eye surgery;
• Glaucoma medications that make the pupil small (like pilocarpine)
• Severe eye injury;
• Previous retinal detachment in the other eye;
• Family history of retinal detachment;
• Weak areas in the retina that can be seen by an ophthalmologist during an eye exam.
If you have risk factors for retinal detachment, know the warning signsand seek immediate medical attention if you have any of these signs.
If you are very nearsighted or if you have a family history of retinal problems, be sure to have complete dilated eye exams on a regular basis. And always wear protective eyewear when playing sports or engaging in any other hazardous activities. If you have a serious eye injury, see your ophthalmologist right away for an exam.
Symptoms of a retinal tear and a retinal detachment can include the following:
• A sudden increase in size and number of floaters, indicating a retinal tear may be occurring;
• A sudden appearance of flashes, which could be the first stage of a retinal tear or detachment;
• Having a shadow appear in the periphery (side) of your field of vision;
• Seeing a gray curtain moving across your field of vision;
• A sudden decrease in your vision.
Floaters and flashes in themselves are quite common and do not always mean you have a retinal tear or detachment. However, if they are suddenly more severe and you notice you are losing vision, you should call your ophthalmologist right away.
Some retinal detachments are found during a routine eye examination. That is why it is so important to have regular eye exams.
Your ophthalmologist can diagnose retinal tear or retinal detachment during an eye examination where he or she dilates (widens) the pupils of your eyes.
An ultrasound of the eye may also be performed to get additional detail of the retina.
Only after careful examination can your ophthalmologist tell whether a retinal tear or early retinal detachment is present.