Flicker perimetry losses in age-related macular degeneration

PURPOSE. To compare static and flicker perimetry outcomes in patients with early age-related macular degeneration (AMD). METHODS. Perimetry was performed in the central visual field of one eye of each of 25 patients with good visual acuity ( > 6/12) and early AMD using static and flickering targets. These results were compared with data obtained from a single eye of 34 age-matched control subjects, 33 of whom were retested at 1 to 3 months after their initial visits. RESULTS. In all cases, patients with early AMD had greater mean defects for flickering than static targets, returning a significantly larger group average in response to flicker (4.3 +/- 0.6 dB) than to static ( 1.8 +/- 0.6 dB; P <0.005). Greater pattern defect losses were also present in AMD-affected eyes with flicker compared with static perimetry ( P < 0.02). These give a higher diagnostic sensitivity for flicker (68% vs. 42%, P < 0.05) at 90% specificity. Sensitivity can be increased to 84% +/- 6% ( specificity 92% +/- 4%) if the criterion for failure is a more than 10-dB loss in the foveal region (1 degrees- 3 degrees). CONCLUSIONS. Flickering targets expose foveal deficits in early AMD better than do static targets. Flicker perimetry is an easy, short procedure that may be useful for monitoring the progression of AMD.