March 11, 2015
3 min read

Patient history, careful retinal assessment key for flashes of light

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ATLANTA – A multitude of conditions can cause a patient to experience flashes of light, Jill Autry, OD, RPh, said, and optometrists must take a thorough patient history, carefully examine the vitreous and retina, and decide if the patient should be followed or referred.

In a course sponsored by Primary Care Optometry News here at SECO, Autry said that flashes of light can be caused by retinal traction, retinal holes, retinal tears or migraine, among other conditions.

Those at risk for vitreous symptoms include older patients with acute or impending posterior vitreous detachment (PVD), those with myopia, patients with lattice degeneration, and those with a history of holes, tears or detachments, she said.

Those who have acute PVD as opposed to retinal detachment typically include older patients, myopic patients earlier than hyperopes, pseudophakic patients earlier than phakic patients, those who experience a quick succession of flashes for 1 to 2 hours, those whose flashes decrease to single flashes, those with increased floaters but one central floater, and those patients in whom the flashes have occurred in the other eye in the past 1 to 2 years.

Patients with flashes should be dilated in both eyes, Autry stressed. Look for pigment in the vitreous, which is a sign of retinal detachment.

Carefully examine the retina of a patient experiencing flashes, she said, and if there are no holes, tears, pigment or blood, see the patient again in 1 week. If there are no retinal findings and the flashes have stopped, see the patient back in 3 to 4 weeks. Discuss the signs and symptoms of retinal detachment with the patient and provide them with after-hours contact information.

Autry recommended referring the patient if you are unsure of your ability to examine the retina. In addition, refer if you find pigment in the vitreous.

A patient reporting small black floaters as well as larger floaters should also be referred, she continued.

“What are you looking for in the vitreous?” Autry asked. “Look for red blood cells. They are much smaller than pigment – it looks like pepper. If the patient had a retinal tear in the past, that pigment will still be there. After cataract surgery, you will see pigment in the anterior vitreous. It may not be pigment from a retinal break.

“Most PVD tears are not hard to see,” she continued. “You’ll see a white operculated hole or tear hanging above the retina. You can miss small tears. That’s why you bring the patient back. The small tears usually stay small, but they can get fluid in them.”

Autry said that inferior detachments are generally not associated with a PVD, but with a small hole somewhere, usually inferiorly in high myopes.

“These patients are asymptomatic,” she said. “It is usually found on routine dilated exams in high myopes. They don’t often have a lot of pigment in the vitreous. I cringe when I’m evaluating a preop LASIK patient who’s -7 D and has never been dilated.”

Patients with migraine often have flashes that move across the field of vision, Autry said.

“It’s different than what we describe with PVD,” she added. “With PVD, you get a jelly kind of thing that is pulsating, then a few days later you’ll get a flash of light.”

Autry said that patients who have had classic migraines throughout their lifetime know what the visual aura is like. She said it usually appears as a jagged flash of light that moves across the visual field and lasts about 10 to 20 minutes.

“If I have an 80-year-old lady seeing this, I think something else, such as ocular ischemic or carotid issues,” she said. “With younger women think migraine.”

Flashes of light in an older patient could be caused by acephalgic migraine, Autry added. This usually occurs in patients who had migraines when they were younger.

“Check them anyway, but it’s probably a visual aura from a history of migraines,” she said. “And they don’t get the headache.”

Other causes of flashes of light include retinal inflammation, retinal vascular occlusion, choroidal tumor, optic neuropathy (compressive or ischemic) and occipital lobe cerebral vascular accident, Autry said.

“Hemorrhage of the retina or inflammation will sometimes spark these flashes of light, as will tumors,” she added. – by Nancy Hemphill, ELS, FAAO

Disclosure: Autry has no relevant financial disclosures.