Many Patients with Age-Related Macular Degeneration Remain Undiagnosed After Eye Exam

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in older people in the United States. AMD affects 14 million U.S. adults, and this number will increase as the "baby boomer" generation ages.

But the extent to which AMD is underdiagnosed in primary care has been unclear.

To determine the degree of AMD underdiagnosis, David Neely, MD, (pictured) and colleagues in the Department of Ophthalmology, School of Medicine, and Department of Epidemiology, School of Public Health at the University of Alabama at Birmingham, did a cross-sectional study of 644 adults who were at least 60 years old.

The medical records of these study participants — their average age being over 69 — indicated they had normal macular health based on the most recent dilated comprehensive eye examination done by a primary eye care ophthalmologist of optometrist. Participants were enrolled in the study from May 2008, through December 2011, and their data was analyzed from May 1, 2016, through December 20, 2016.

Three-field, digital color fundus photographs of the eyes of each participant were taken and used by an experienced, trained, masked grader to determine whether or not these eyes actually had AMD as defined by the Clinical Age-Related Maculopathy Staging system.

Although the team found that 968 of 1,288 eyes — or 75% — had no AMD, they also found that 320 of 1,288 eyes — 25% — had AMD despite the absence of such a diagnosis in the medical record.

Regarding eyes with AMD that went undiagnosed during the last dilated eye exam, 10% had hyperpigmentation, and 13% had hypopigmentation. Moreover, 78% had small drusen, 78% had intermediate drusen, and 30% had large drusen. In their study report, the team noted that these large drusen diagnoses were consistent with a diagnosis of intermediate AMD, which would have been treatable with nutritional supplements if diagnosed during the dilated eye exam.

The prevalence of undiagnosed AMD did not differ between ophthalmologists and optometrists (age-adjusted odds ratio (OR), 0.99; 95% confidence interval (CI), 0.71—1.36; P = 0.94). However, undiagnosed AMD was associated with older patient age (OR, 1.06; CI, 1.04–1.09; P < 0.001), male sex (OR, 1.39; CI, 1.02–1.91; P = 0.04), and having less than a high-school education (OR, 2.40; CI, 1.03–5.62; P = 0.04).

The study team concluded that if one in four patients with AMD go undiagnosed with the current methods used in primary eye care, underdiagnosis is not uncommon. However, they added the reasons underlying AMD underdiagnosis in primary eye care "remain unclear.”

In addition, these findings indicate that improvements in diagnostic methods are needed for early detection. According to the study team, this need will increase with the development of new treatments for the earliest stages of AMD.

Although no proven effective treatments for early AMD currently exist, treatments targeted towards early AMD are the next frontier of development. As a result, accessing the benefits of new interventions for early AMD will depend increasingly on correct, prompt, early detection of AMD.

The report, “Prevalence of undiagnosed age-related macular degeneration in primary eye care,” was published online on April 27, 2017, in JAMA Ophthalmology.