Hemispherical focal macular photopic negative response and macular inner retinal thickness in open-angle glaucoma.

PURPOSE: To investigate in open-angle glaucoma the focal macular photopic negative response and spectral-domain optical coherence tomography measurements of retinal thicknesses in the superior and inferior macula.
DESIGN: Comparative case series.
METHODS: We studied 63 eyes of 63 patients with open-angle glaucoma and 41 normal eyes of 41 volunteers. Photopic negative responses were recorded using a spotlight (diameter of 15 degrees of circle), projected onto the whole or superior or inferior macula. Ganglion cell complex (nerve fiber + ganglion cell + inner plexiform layers) thickness was measured using spectral-domain optical coherence tomography.
RESULTS: Mean photopic negative response amplitude over the entire macula was significantly (P < .001) decreased compared with that of controls in eyes with early (n = 24; to 62.1%), moderate (n = 21; to 57.2%), and severe (n = 18; to 49.3%) open-angle glaucoma, but not significantly different among eyes with various stages of glaucoma. Mean ganglion cell complex thickness was significantly (P < .001) decreased compared with that of controls in eyes with early (86.0%), moderate (78.3%), and severe (71.2%) glaucoma, and thinning correlated positively with glaucoma severity (P < .001). Mean photopic negative response amplitude correlated significantly (P < .001) with ganglion cell complex thickness over the whole, superior, and inferior macular areas (r = 0.57 to 0.74). In 16 eyes without visual field defect in the inferior hemifield, mean photopic negative response amplitude was 56.5% of normal (P < .001), and mean ganglion cell complex thickness in the superior macula was 92.1% of normal (P = .004).
CONCLUSIONS: Focal macular photopic negative response amplitude correlates with ganglion cell complex thickness, but decreases more abruptly in early glaucoma compared with ganglion cell complex thickness.