Congenital grouped pigmentation of the retina is a rarely encountered condition; Stephenson1 found only 3 instances of this anomaly in a series of 2,400 examinations, while Blake2 noted not more than 7 cases of this kind in twelve years of ophthalmologic practice. The clinical picture of grouped pigmentation, as well as the characteristic features distinguishing it from abnormal multiplication due to a progressive pathologic process, were excellently described by Stephenson.
The changes which occupy a sector-like portion of the fundus, consist of groups made up of black to dark chocolate brown spots, which, as seen by the direct method, range in size from 0.5 to 2 mm., or more; in general terms it may be said that the farther away the spots lie from the optic disk the larger they become.
This specific hyperplasia of the pigmented cells of the retina is listed in the literature under various
PAUL TOWER. CONGENITAL GROUPED PIGMENTATION OF THE RETINAReport of Two Cases. Arch Ophthalmol. 1948;39(4):536–541. doi:10.1001/archopht.1948.00900020544008