Flashes of light or floating bits that suddenly appear across your line of vision might be a sign of a serious eye problem that if left untreated, could cause blindness, researchers are warning.

A review conducted by researchers from Queen's University and Hotel Dieu Hospital in Kingston finds that one in seven patients with the sudden onset of these symptoms has a retinal tear -- or worse: a retinal detachment that would cause permanent blindness.

The researchers looked at nearly 200 articles involving retinal tearing and performed a meta-analysis of 17 articles. They found that a retinal tear occurred in 14 per cent of patients who reported seeing floaters and/or light flashes.

The research is published on the Journal of the American Medical Association website.

In retinal tearing, the thin layer of light-sensitive tissue on the back wall of the eye begins to peel away from the supportive tissue. Tearing is often an age-related event, and its likelihood grows with age. But it can also occur to those with degenerative myopia and other eye conditions, or to those who have had an eye injury.

Eye specialist Dr. Sanjay Sharma, a professor of Ophthalmology and Epidemiology at Queen's, says retinal tears can usually be repaired with laser treatment if detected by a doctor. "But if fluid gets in under the retina and causes it to detach, it may be too late."

He notes that retinal tears are extremely difficult to detect except with high-tech equipment and a thorough peripheral retinal examination.

He says anyone with the sudden symptoms of floaters or light flashes should seek immediate medical treatment.

By the same token, doctors with patients who report such symptoms should be referred to an ophthalmologist quickly for a thorough examination.

"Since retinal tear can lead to detachment in up to 50 per cent of cases, new floaters and flashes is a medical condition that needs urgent assessment," Sharma says.

Sharma notes that many people experience floaters in dim light or while staring at a white surface. In most cases, floaters are part of the natural aging process and simply an annoyance.

But the sudden onset of dots or cobweb-like floaters that don't go away, or flashes in the eye like fireworks, could mean a retinal tear or detachment, especially in older people.