Hemianopic offsets in the visual field of patients with glaucoma.

In 359 glaucoma patients (600 eyes), we measured the peripheral field with kinetic targets and the central 30 degrees field of vision with static testing, using the Field-master-5000 automated perimeter to evaluate the prevalence and significance of step-like visual-field defects along the vertical midline (a hemianopic offset). In all, 129 eyes of 121 patients had a hemianopic offset. In 108 eyes the offsets (involving either the peripheral or the central field or both) were associated with other glaucomatous field changes, whereas 21 eyes showed a peripheral offset as an isolated finding. Of the 8 cases of offsets found in both eyes, 7 were binasal and 1 occurred bitemporally but in separate hemifields. This study suggest that hemianopic offsets occur commonly in glaucoma patients but have limited diagnostic value because most are associated with other glaucomatous field changes. However, these findings help in distinguishing glaucomatous offsets from those caused by neurological lesions.