If you cut your finger or twist your ankle, it hurts. But when something bad happens to one of your retinas, the light-sensitive tissue at the back of your eyes, you feel no pain. Your retina, the part of your eye that sends visual information to the brain, can be torn or even detached from its blood supply without causing you a bit of discomfort.
But no pain doesn’t mean no symptoms. In fact, eye doctors say, there are clear warning signs that everyone should know. That’s because, “generally, the sooner the patient is diagnosed and treated, the better the outcome,” says Purnima Patel, an associate professor of ophthalmology at the Atlanta Veterans Affairs Medical Center and a spokesperson for the American Academy of Ophthalmology. Over a lifetime, about 3 in 100 people will experience a detached retina. That makes it much less common than major causes of vision loss, such as glaucoma and cataracts. But the consequences can be serious. When the retina peels off the back of your eye — like wallpaper sloughing off the wall of a steamy bathroom — it can’t do its job. Left untreated, a detachment can cause permanent vision loss or blindness in the affected eye. The most common kinds of detachments happen after a tear develops in the tissue-thin retina, allowing fluid to seep behind the retina and loosen it. Retinal tears most often are triggered, in susceptible people, by what start out as normal changes in the aging eye.
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The most important changes to watch for:
1. Lots of new floaters
Floaters are specks that seem to appear before your eyes but really come from inside your eyes. They “can look like spider webs, or bugs floating in your vision, or just like a little bit of a dark swirl,” Patel says.
The specks tend to be more noticeable in bright light, especially when you look at a white background, says Philip Ferrone, president of the American Society of Retina Specialists and a professor of ophthalmology at Hofstra University. Floaters you’ve had for a while generally aren’t cause for concern. But anytime a new crop suddenly appears, you should pay attention, Patel and Ferrone say. Floaters often are caused by age-related changes in the ball of gel that fills the space between the lens near the front of your eye and the retina in the back. This gel ball, called the vitreous, shrinks and becomes more liquefied as you age, creating blobs and strands picked up in your vision. Typically, around age 60 or so, the vitreous pulls away from the retina, Ferrone says. That separation, called a posterior vitreous detachment, can cause a small amount of bleeding and a sudden increase in floaters, he says.
The problem: That separation also occasionally tears the retina, which can lead to a retinal detachment.
Eye changes associated with diabetes and other diseases also can cause floaters.
2. Flashes of light
If you see brief flashes of light or lightning streaks in your field of vision, think of it as a message from your retina, Ferrone says. “Flashes mean something is pulling somewhere,” he says. “It means the retina is being stimulated. So it’s either being stimulated by the gel pulling on it, in the process of the gel separating, or in the process of a retinal tear forming.” Though gel separation is harmless, tears are not, and you can’t tell one from the other by the nature of the flashes, he says. “Flashing lights mean something and they can mean something relatively innocuous … or they can mean something bad,” Ferrone says.
Note: Some people with migraines — a spasm of blood vessels in the brain that can happen with or without headaches — see flashes of light in jagged lines or heat waves that last up to 20 minutes or so. Flashes associated with retinal tears tend to be briefer.
3. A shadow or curtain
If your retina has already begun to detach from the back of your eye, you may experience a more definite symptom: a dark shadow or curtain over part of your vision. Patel says the curtain may be come from the side, top or bottom of your vision. Once it appears, it doesn’t disappear, and it may grow larger.
Though a shadow on your vision might seem alarming to most people, both Patel and Ferrone say they see patients who manage to ignore this warning siren.
“Some people just say, ‘Oh, I’ll take care of that whenever. I’m not too worried about it, it’s not hurting me and I can still see,’ ” Ferrone says.
But that kind of delay can cost you your vision.
What to do next
When you see lots of new floaters, flashes of light or a shadow on your vision, you should get checked out promptly, within 24 to 48 hours, ideally by an ophthalmologist, a medical doctor specializing in the eye. Some ophthalmologists have extra training as retina specialists and are the most experienced at diagnosing and treating retinal tears and detachments. If you don’t know whom to call, you can ask your primary care doctor for a referral.
What will happen then
The ophthalmologist will put drops in your eyes to dilate, or widen, your pupils and then look through a special lens at your retina. To get a better view, the doctor also may press down on your eye. Some will take pictures or use an ultrasound. If a small tear is found, you might be treated immediately with a laser. More advanced tears and detachments typically require surgery, usually performed within a few days. Several different techniques are used. Most people end up with vision close to what they had before the tear or detachment. But in cases where the center part of the retina, called the macula, has pulled away, full vision may not be restored
And if there is no tear or detachment? That’s what happens in most cases of floaters and flashes, Ferrone says. But, to be safe, you may be asked to return in a month for another check. If there are signs of bleeding, you might be asked to come back in a week, he says.
Who’s most at risk?
These factors can raise your risk of a retinal tear or detachment:
- Nearsightedness. The longer shape of the myopic eye puts the retina under extra stress, increasing your risk.
- Recent eye surgery. If you are planning surgery, your surgeon should discuss the risks.
- Eye injuries. Trauma can sometimes cause tears and detachments.
- A family history of retinal detachment.
- Thin areas on your retina that may be picked up on routine eye exams.
- Diabetes. People with diabetes-related eye disease can develop scar tissue on their retinas, increasing the risks of detachment.
Source: National Institutes of Health, National Eye Institute