HISTOLOGICAL FINDINGS IN A CASE OF ANGIOID STREAKS

Abstract

Bruck''s membrane in the posterior part of the fundus was strongly basophilic and varied in thickness. More anteriorly it was only partially basophilic and beyond the equator it was non-basophilic. There were 3 gaps in Bruck''s membrane which occurred at points of relative weakness of the membrane, the rupture being followed by a widening of the gap due to retraction of the normal elastic tissues in the choroid. The retinal pigment epithelium and choriocapillaris related to the gaps were unchanged. Bruck''s membrane contributes to the brightness of the fundus on ophthalmoscopic examination by obscuring the choriocapillaris. When there is a gap in the membrane, the light striking the gap is absorbed by the choriocapillaris and appears as a streak. The basophilic condition of Bruck''s membrane may be due to calcification occurring as a senile phenomenon, or following precocious senility of elastic fibers. The hemorrhages often associated with angioid streaks may be due to rupture of the underlying choriocapillaris in fracture of the calcified Bruck''s membrane.