Article

Closing the Gap in AMD Diagnosis

HOW TO STAY AHEAD OF VISION LOSS USING NEW TECHNOLOGIES AND EVIDENCE-BASED MANAGEMENT

IT IS ESTIMATED THAT 15 MILLION North Americans currently have age-related macular degeneration (AMD).1 What’s more, AMD is the leading cause of central vision loss in people older than 50 years in the United States.1 Despite treatment advances, such as vascular endothelial growth factor (VEGF) inhibitors for the neovascular form of AMD, the disease progresses to end-stage severe vision loss in a significant number of people. The number of AMD cases will continue to increase as the population ages (Figure 1).

Figure 1. AMD is on the rise, and the number of cases is expected to increase.

As primary eyecare clinicians, optometrists are uniquely positioned to identify at-risk patients and those presenting with early signs of AMD. This position is strengthened because we have reached a new era in early detection and monitoring. New parameters — such as low-luminance deficits, glare disability, reduced macular pigment optical density, and dark adaptation abnormalities — have been shown to be potential early disease markers. Additional genetic variants associated with AMD have been identified. Also, diagnostic testing has advanced with the availability of technologies, such as OCT angiography, which enables non-invasive assessment of the retinal vasculature, and ultra-widefield imaging, which provides a view of retinal health beyond the macula.

By combining traditional retinalexamination methods with new technologies to detect AMD at its earliest stages, optometrists can take action to safeguard patients’ vision by recommending individualized disease management plans. We can be proactive in several ways, including targeted patient education and implementation of evidence-based nutrition management. Much can be done before anti-VEGF injections are needed in an effort to prevent the catastrophic vision loss that some patients may eventually suffer.

Recent Studies

Several studies have shown a need for improvement in detection of AMD. In one study, for example, investigators enrolled 644 patients age 60 or older who were deemed to have normal macular health, according to the record of their most recent dilated eye examination with a primary ophthalmologist or optometrist.2 When masked graders evaluated color fundus photographs, 25% of patients were found to have AMD as defined by the Clinical Age-Related Maculopathy Staging system.2 Furthermore, approximately one-third of those patients had AMD with large drusen, which the paper authors noted “would have been treatable with nutritional supplements had it been diagnosed.2

In another study with 95 patients, an anterior segment ophthalmologist found that 60% of the 95 patients had AMD based on dark adaptation testing.3 I completed a similar study with 100 patients older than 60 in my practice. The results aren’t yet published, but in 40% of the patients, fundus examination and OCT were normal, but dark adaptation was impaired, meaning 40% had macular degeneration that would have remained undetected without appropriate testing.

Proactive Care

As these and other studies indicate, although the prevalence of AMD is increasing, too many AMD patients are not being identified. Our discussion will illustrate how optometrists can change this by utilizing the latest diagnostic technologies to identify AMD patients sooner. Once diagnosed, patients can be counseled and managed appropriately in an effort to slow or stop progression to more serious disease and loss of vision. The optometrists taking part in this discussion represent different practice types, including private optometric practices, a retina/macula specialty practice, and the U.S. Department of Veterans Affairs. However, they all share a firm commitment to appropriately diagnosing and managing AMD patients until they may require intervention by a vitreoretinal specialist. Here, they share information about their tools and techniques. ■

REFERENCES

  1. Age-related macular degeneration. American Academy of Ophthalmology. Available at: https://www.aao.org/bcscsnippetdetail.aspx?id=9711f063-ed7b-452b-8708-c4dad0d893e8 ; last accessed April 20, 2018.
  2. Neely DC, Bray KJ, Huisingh CE, Clark ME, McGwin G Jr, Owsley C. Prevalence of undiagnosed age-related macular degeneration in primary eye care. JAMA Ophthalmol. 2017;135(6):570-575.
  3. Weis R, Henderson TT. Prevalence of subclinical AMD in patients in a general ophthalmology practice. Poster 1513-B0914 presented at: The Annual Meeting of the Association for Research in Vision and Ophthalmology; May 8, 2017; Baltimore.