Delayed RMDA predicts AMD incidence, progression

Delayed rod-mediated dark adaptation (RMDA) is associated with the incidence and progression of age-related macular degeneration (AMD) over 3 years in healthy eyes or those with early AMD at baseline, reports a study.

Eyes of older adults aged ≥60 years with normal macular health or with early AMD at baseline were included in this longitudinal study.

The Age-Related Eye Disease Study (AREDS) 9-step classification system was used to establish AMD presence and severity in eyes that underwent fundus photography at baseline. RMDA, scotopic sensitivity, low-luminance acuity, mesopic contrast sensitivity, mesopic light sensitivity, visual acuity, and contrast sensitivity were tested in one eye at baseline.

At 3-year follow-up, the authors repeated fundus photography and the AREDS classification. They assessed the association between visual functions and AMD incidence and progression using age-adjusted relative risks and 95 percent confidence intervals (CIs) for the study eye and the fellow eye at follow-up.

Compared with eyes without delays, those with delayed RMDA were 3.54 or 3.40 times more likely to have incidence AMD in the study and the fellow eye, respectively, at 3 years. Low-luminance visual acuity in the study eye also correlated with AMD incidence.

Similarly, eyes with early AMD at baseline with delayed RMDA had 3.89- or 2.65-fold higher likelihood of progression at follow-up for the study and fellow eye, respectively. No other visual functions showed a significant association with AMD progression at follow-up.

“Our results suggest that other visual functions are not useful for understanding AMD incidence and early progression risk,” the authors said.

“Interventions that eventually are designed to arrest early AMD progression or preventative measures in those at risk should consider RMDA a functional outcome measure,” they added.