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Flashes of light can be a sign of a dangerous eye condition

Screen Shot 2016-08-01 at 11.27.07 AMBY JILL U. ADAMS
Have you ever had black specks floating around in your vision? Patrick Muffler noticed some one day.

“I saw funny V-shaped floaters in my eye,” he says. When he woke up the next day, a Friday, they were still there. “I started getting more — black dots, maybe 40 of them.”

Over the weekend, Muffler, a retired geologist in Palo Alto, Calif., developed a cloudy area in his visual field.

He went to his ophthalmologist that Monday morning and learned that his retina was torn and detached. “If I hadn’t gone to the doctor, I would have gone blind in that eye,” he says.

Anyone can get floaters — or sometimes light flashes — in their eyes. Floaters can take different shapes, including spots, threads and clumps. Sometimes the cause is benign — bits of cell debris drifting about in the fluid that fills your eyes — and sometimes it’s an urgent and serious condition. If you experience a sudden increase in floaters and/or flashes, you should seek medical care.

The eye is filled with a gel-like substance called the vitreous humor. “As we get older, condensations can form in the gel, like strands in jello,” says Sonia Mehta, an ophthalmologist at Wills Eye Hospital in Philadelphia. These condensations appear as floaters.

Young people can experience floaters, but it’s more common in your 50s and 60s. As people age, the structure of vitreous humor changes, from gel to liquid. As the gel shrinks, it can pull on the retina — the light-receiving membrane at the back of the eye that transmits images to the brain — and cause light flashes, says Rahul Khurana, a retina specialist in the San Francisco Bay area and a clinical spokesman for the American Academy of Ophthalmology. “It’s a bit like looking at the headlights of a Mack truck — not something you’d miss.”

Migraines can also cause light flashes: Some people experience migraine’s visual symptoms, which look like zigzag patterns at the edges of one’s field of vision, without headache.

Because flashes can arise from different conditions, it’s wise to get the symptoms checked out right away. And yet many people put off seeing a specialist. That’s a mistake, Mehta says. Early intervention — often just with a simple procedure done in a doctor’s office — is important: An increase in floaters or flashes indicates that something is happening in the eye, and only an eye exam can distinguish between a something that’s no big deal and a something that could lead to blindness.

Here’s what can happen to cause floaters and flashes.

You might just have benign floaters caused by cellular debris or condensation in the gel. Sometimes when the gel turns more liquid, the debris moves around more and you notice the change. Or your vitreous gel may be changing structure and tugging on the retina. This also is generally harmless.

The change from gel to a more liquid form happens to everyone, Mehta says. It’s very rare before age 40, but 60 to 80 percent of people will have gone through the transition by age 65.

A change in the eye’s vitreous structure can tear the retina, an injury that requires urgent treatment. If not addressed, that tear can advance to a detachment, in which the retina comes away from its base.

“A tear can be easily fixed in an office visit,” Khurana says.

Left untreated, the retina can detach from the back of the eye. In that case, “you might see something like a curtain or shade being pulled over the eye,” Mehta says. The retina loses its blood flow and nutrient source, and it will start to die. Without medical attention — involving more-invasive surgery and a weeks-long recovery period — permanent vision loss will result.

In Muffler’s case, his regular ophthalmologist referred him to Khurana, who extracted the vitreous humor and placed a gas bubble at the back of Muffler’s eye. The pressure from the bubble held the retina in place while the surgical wound healed. “The gas bubble stays in for two weeks,” Muffler says. “I canceled a trip to Europe.”

The American Academy of Ophthalmology recommends that people older than 40 get an exam for a baseline measure of eye health even if their vision seems to be fine. “Our eyes go through changes with age, the same as the rest of our bodies,” Khurana says. A bonus benefit of a baseline eye exam is that you’ll have an eye doctor to call should you ever experience new flashes or floaters.

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