This cross-sectional study examined the prevalence of undiagnosed AMD among patients reported by their primary care ophthalmologist or optometrist to have healthy maculas.
Investigators enrolled 644 adults 60 years or older from eye care practices in Birmingham, Alabama, whose medical record notes showed no finding of signs of AMD from their most recent comprehensive dilated exam. Subsequently, 3-field digital color fundus photographs were taken of both of each subject’s eyes and evaluated by an experienced grader for presence and severity of AMD using the Clinical Age-Related Maculopathy Staging (CARMS) system.
Of 1288 total eyes, 968 (75.2%) were found to have no AMD according to the CARMS system, and were thus in agreement with their medical records. However, the grader found 320 eyes (24.8%) had AMD despite no diagnosis in the medical record.
Among the newly-identified AMD eyes, 220 (68.8%) had early AMD, 99 (30.9) had intermediate AMD, and 1 (0.3%) had geographic atrophy (GA). The authors noted that over three quarters of previously undiagnosed eyes had 10 or more small and/or intermediate drusen (77.8% and 78.1%, respectively), and 30% had large drusen. No eyes had serous retinal pigment epithelial detachment, choroidal neovascular membrane, or disciform scar.
Patients were more likely to be undiagnosed for AMD if they were older, male, had less than a high school education, had worse visual acuity, or were pseudophakic or hypertensive. Other factors, including family history of AMD or time since last exam, were not different between the 2 groups.
The same proportion (2.2%) of patients with healthy maculas and undiagnosed AMD were taking AREDS nutritional supplements. However, all 96 subjects with large drusen would be candidates for supplementation to help slow disease progress.
Key take-home points:
- This article is notable for reporting that approximately 25% of eyes examined by primary eye specialists (both optometrists and ophthalmologists) were not diagnosed with AMD despite having macular characteristics consistent with that diagnosis.
- The data reinforces the importance of a complete eye examination every 1 to 2 years for those over age 65—the age group at greatest risk of macular degeneration—even in the absence of symptoms. This is particularly relevant for patients with cataract, as even a small opacity may obscure signs of disease on the retina.
- While important, the results are not surprising: diagnoses by an experienced retina specialist using photographs will always be more sensitive than a general ophthalmologist or optometrist performing an office-based exam on a moving, blinking subject.
- This study raises concerns over how dilated examinations may be improved or augmented with imaging to improve early detection of macular degeneration.
- It may call into question the use of normal, control eyes in macular degeneration studies given that a substantial percentage of older adults’ so-called ‘healthy’ eyes on clinical examination may actually have undiagnosed macular degeneration.