Eye Care Providers May Not Spot Macular Degeneration

Primary care optometrists and ophthalmologists may sometimes fail to detect age-related macular degeneration, the most common cause of vision impairment in the elderly, a recent U.S. study suggests.

Researchers examined data on a total of 1,288 eyes from 644 older adults who got what’s known as a dilated eye exam, when clinicians widen the pupils with eye drops to let in more light and get a better look at the retina in back of the eyeball.

Based on these exams, none of the participants were diagnosed with age-related macular degeneration by primary care optometrists and ophthalmologists. But when retina specialists took another look, they diagnosed the eye disorder in 25 percent of cases.

“To our knowledge, this is the first study to address the extent to which age-related macular degeneration (AMD) is under-diagnosed by primary eye providers in the U.S.,” said lead study author Dr. David Neely, a researcher at Callahan Eye Hospital and the University of Alabama at Birmingham.

“As treatments for the earliest stages of AMD are developed in the coming years, correct identification of AMD in primary eye care will be critical for routing patients to treatment as soon as possible so that the disease can be treated in its earliest phases and central vision loss avoided,” Neely said by email.

About 14 million Americans have age-related macular degeneration, and as the baby boomer population ages, the ranks of patients with this disorder are expected to swell, the researchers note in JAMA Ophthalmology.

It happens when a part of the retina called the macula gets thinner with age. Over time, people with the condition can lose what’s known as central vision, or the ability to see things in detail when facing them head on. They can become unable to read books or see the road well enough to drive a car, but they may retain some peripheral vision.

There’s no cure, but there are some medications and laser procedures on the eye that can sometimes slow the progression of the disease and help avoid extensive vision loss. Eating plenty of leafy greens and avoiding cigarettes may help prevent the condition from developing.

Patients in the current study were 69 years old on average. They were seen by one of 31 primary eye care providers in Birmingham, Alabama, between 2009 and 2011.

They were more likely to have undiagnosed age-related macular degeneration if they were older, male or had less than a high school education.

One limitation of the study is that results from practices in one region might not necessarily reflect how accurately age-related macular degeneration would be diagnosed elsewhere, the authors note.

There’s also wide variation in severity with this condition, said Dr. David Parke II, chief executive officer of the American Academy of Ophthalmology.

“It’s a little like a person saying `I have high blood pressure,’” Parke, who wasn’t involved in the study, said by email. “It can be just borderline high and difficult to detect or it can be dangerously high leading to a high risk of stroke or heart attack.”

It’s not surprising that good quality, high magnification images of the macula interpreted by a trained ophthalmologist retina specialist catch more subtle changes in the eye, Parke added. But it’s also more expensive than traditional dilated eye exams done by primary eye care providers and won’t necessarily catch many additional cases of AMD in people who don’t have symptoms, he said.

As the condition worsens, some previous research suggests that nutritional supplements with ingredients including zinc, copper, and vitamins C and E may help minimize vision loss.

“For many patients with more severe AMD the use of nutritional supplements can reduce the subsequent rate of worsening of AMD and vision loss,” said Dr. Paul Lee, director of the W.K. Kellogg Eye Center at the University of Michigan in Ann Arbor.

“One piece of good news is that AMD is generally something that progresses over years, so that if detected on the next visit, there is still the opportunity to have the therapy started then,” Lee, who wasn’t involved in the study, said by email.