This is the first description of the biomicroscopic appearance of reticular cystoid degeneration (RCD). The case with exceptionally large RCD illustrates the difficulties of diagnosis in the living eye of this rather common condition. There is no scotoma in the visual field and the pillars transgressing the cystoid spaces obviously contain nervous elements. Morphologically the RCD are not very conspicious and are easily confounded with typical cystoid degenerations. Differential diagnosis between these two cystoid alterations of the retina is therefore difficult and possible only if vessels on the outer layer of the cystoid spaces are found.