Purpose: To determine the overlap in defective visual field locations between the right and left eyes of primary open-angle glaucoma patients.
Design: Cross-sectional retrospective analysis of data from a prospectively designed longitudinal study.
Participants: Patients with glaucomatous optic neuropathy in at least 1 eye and 2 consecutive reliable standard automated perimetry fields within 15 months were included, yielding 468 eyes of 234 patients.
Methods: Concordance in defective visual field locations between right and left eyes were calculated as the number of overlapping locations divided by the total number of defective locations (intereye concordance ratio). Concordance ratios also were calculated within an eye over time (intraeye concordance ratio) and between unmatched pairs of fields (unmatched concordance ratio).
Results: Intereye concordance (0.24+/-0.02) was significantly smaller than intraeye concordance (0.37+/-0.02) and significantly larger than unmatched concordance (0.14+/-0.01). There was a significant interaction between concordance type and defect size, such that there was no difference in concordance ratios for defects of fewer than 8 locations, and the difference between intereye concordance versus intraeye concordance and unmatched concordance ratios increased with larger defect sizes.
Conclusions: A spatial relationship exists between defective locations of an individual's eyes. Future studies will show whether information about the spatial relationship is useful to guide the modification of visual field test locations to improve detection of loss and perhaps also progression.