Chorioretinal juncture. Vascularization of Bruch's membrane in peripheral fundus
R. Y. Foos and M. T. Trese
Pathologic changes in chorioretinal juncture (pigment epithelium, drusen,
Bruch's membrane, and choriocapillaris) were studied in the peripheral
fundus of eyes removed at autopsy and surgically enucleated eyes by gross,
light microscopic, and electron microscopic methods. Vascularization of
Bruch's membrane (VBM) occurred in 430 (43%) of eyes at autopsy, was age
related, and was most common in the ora zone and temporal sectors; a
significant correlation was found with systemic oligemic conditions.
Vascularization of Bruch's membrane occurs in the inner collagenous layer
of the membrane, which always demonstrates collagenous thickening and often
shows intrusion of interstitial-type cells; the vessels emanate from
adjacent pars plana. While many degenerative changes of the pigment
epithelium accompany VBM, only direct ophthalmoscopic visualization of
linear-dendritic depigmentation of overlying pigment epithelium provides
diagnostic evidence of vessels. Thus, VBM seems pathogenically related to
the fact that the peripheral fundus is a vascular watershed and is
selectively vulnerable to senile involutional changes.
