Enlargement of the blind spot caused by papilledema.

Blind spot enlargement in papilledema has been attributed to either mechanical disruption of the integrity of the peripapillary percipient elements by the swollen optic disk or to the Stiles-Crawford effect. We investigated the possibility that blind spot enlargement in papilledema is caused, at least in part, by a refractive scotoma due to peripapillary hyperopia. We reduced the enlarged blind spot in a patient with focal peripapillary hyperopia, without papilledema, to near normal size by using progressively stronger plus lenses. Similarly, with the addition of plus sphere, we reduced the size of the blind spot in five of six patients with papilledema, but in none of our normal subjects.