Acute sectorial choroidal ischemia.

Four eyes (of three patients) with sectorial choroidal ischemia by temporal arteritis or carotid obstruction underwent fluorescein angiography during and after the acute phase. In all cases hypoperfusion affected the whole temporal choroid; however, disturbance of retinal pigment epithelium was much less extensive. In two cases the retinal pigment epithelium became necrotic and scarred within a limited area that was typically triangular in shape; in the third case scarring was limited to some pigmented streaks, and in the fourth case, retinal pigment epithelium remained normal. The triangular scar that appeared after episodes of choroidal hypoperfusion did not seem to be a true reflection of the extent of the choroidal artery obstruction in the acute phase. Our observations suggest that the deficient choroidal perfusion involved more than the choroidal artery supplying the triangular area of pigment epithelium disturbance. Several mechanisms (for example, retrograde venous filling, restoration of perfusion) reduce the deleterious effects of ischemia. Thus the necrosis of the retinal pigment epithelium would appear in only those sectors where ischemia was particularly severe or prolonged.