Flicker perimetry losses in age-related macular degeneration

To compare static and flicker perimetry outcomes in patients with early age-related macular degeneration (AMD).

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.

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 ).

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.