Dark Adaptation Testing to Help Identify and Monitor AMD

ALSTAR Study: The Science Behind Dark Adaptation

The Alabama Study on Early Age-Related Macular Degeneration (ALSTAR study) tracked 325 adults age 60 and older. Each subject had normal macular health, as verified by clinical exam and grading of fundus photographs. When dark adaptation speed was assessed, 24% of subjects showed dark adaptation impairment at baseline.

Three years later, the subjects with impaired dark adaptation were two times more likely to have AMD and eight times more likely to have advanced beyond the earliest stage of AMD. In fact, the study showed a positive correlation between degree of dark adaptation impairment and severity of AMD. At the follow-up visit, all subjects with severe AMD were identified as having dark adaptation impairment at baseline.

The ALSTAR study was groundbreaking because it demonstrated dark adaptation impairment indicates AMD at least three years before the disease is clinically evident.

Functional Testing to Detect AMD and Monitor Disease Progression

Considering dark adaptation is impaired years before structural changes in the macula are observed, assessing dark adaptation function can be invaluable in detecting subclinical AMD. Identifying patients at the earliest stages of the disease allows for intervention when risk reduction strategies and ongoing monitoring are most beneficial to the patient.

Improve Ability to Diagnose AMD

A landmark study published in JAMA Ophthalmology shows at least 25% of clinical AMD is going undiagnosed in primary eye care today. Moreover, 30% of the undiagnosed patients had large drusen, a known risk factor for advanced AMD (wet AMD).

Complementing structural exams with functional dark adaptation testing helps safeguard against failure to catch clinically-detectable AMD. Dark adaptation testing provides a clear, objective measure that can be used to identify AMD with 90% sensitivity.

Ongoing Disease Management

For a patient with AMD, more frequent retinal exams are recommended to monitor disease progression — increasing from a 12-month to a six-month follow-up interval. More frequent visits and testing provide the clinician with a better chance to detect choroidal neovascularization (CNV) before visual acuity loss. For patients who are progressing rapidly or are at high risk for CNV, the follow-up visit interval may be shortened to every three or four months. Dark adaptation testing, together with structural tests like OCT, will help determine the severity of the disease and desired frequency of follow-up exams.

Improve Patient Outcomes with Early Diagnosis

Early detection of dark adaptation impairment is important. Dark adaption testing can help doctors provide patients with an earlier AMD diagnosis, with the hope of delaying or reducing the risk of blindness caused by this chronic and progressive disease.

For more information about the benefits of dark adaptation testing with the AdaptDx Pro^®, contact MacuLogix. The AdaptDx Pro is supported by our AMD Excellence Program^® – a core component of every device subscription.