The Full-field Flicker Test in Early Diagnosis of Chronic Open-angle Glaucoma

Abstract

To evaluate whether the full-field flicker test, a psychophysical test employing full-field flickering stimuli to measure temporal contrast sensitivity, can detect glaucomatous optic nerve damage in patients with increased intraocular pressure and glaucomatous optic disk abnormalities but normal visual fields. Temporal contrast sensitivity was determined with a sinusoidally flickering light (frequency, 37.1 Hz) of constant mean photopic luminance (10 cd/m2) presented in a full-field bowl of 58-cm diameter. The prospective study included three groups of individuals: the "preperimetric" glaucoma group of 80 patients with increased intraocular pressure, glaucomatous optic disk abnormalities, and normal visual fields; the "perimetric" glaucoma group of 56 glaucomatous patients with increased intraocular pressure and glaucomatous changes of the optic disk and visual field; and the control group of 96 normal subjects. Temporal contrast sensitivity was significantly (P < .001) lower in the two glaucoma groups than in the control group. In the preperimetric glaucoma group, 34% of the patients (27/ 80) were recognized by the full-field flicker test at a specificity of 99%. For all study subjects, temporal contrast sensitivity decreased significantly (P < .001) with decreasing neuroretinal rim area, enlarging peripapillary atrophy, and diminishing retinal nerve fiber layer visibility. The full-field flicker test can detect glaucomatous optic nerve damage in patients with increased intraocular pressure, glaucomatous optic disk abnormalities, and normal visual fields. Considering its feasibility, simplicity, quick performance, and low costs, the full-field flicker test may be helpful in clinics and in screening examinations as a supplement to glaucoma diagnosis.