Clinical detection of early glaucomatous foveal involvement

The aim of our study was to verify whether threshold testing of the central area with a common automated perimeter could detect early glaucomatous damage. We selected 9 eyes of 9 patients with suspected primary open angle glaucoma and normal visual fields and 18 eyes of 18 age-matched normal subjects. They underwent the Macula Threshold Test of the Humphrey Field Analyzer using white and blue targets. We found no significant difference in retinal sensitivity to white targets between the two groups. Sensitivity to blue targets was significantly lower among glaucoma suspects (18.43 +/- 1.14 dB) than in the control group (22.37 +/- 0.94 dB) p less than 0.001). Blue thresholds related significantly to age only in normals (p = 0.028) while in glaucoma suspects they were strongly related to vertical cup/disc ratios (p less than 0.001). These results suggest that it is possible to detect early central visual disturbances from glaucoma using an automated perimeter and its built-in color filters.