Progress in retinal imaging today allows better detection of intraretinal changes than has ever been possible. Despite the limited definition of time domain OCT, it has greatly improved our understanding of macular diseases, especially of the various kinds of hyporeflective or optically empty spaces in the retina. Spectral domain OCT and ultra-high resolution OCT show the details of abnormal intraretinal structures with even greater precision. However, there is still some ambiguity about differentiating between various macular disorders, whose common feature is the presence of cystoid spaces, probably because we do not completely understand their pathogenesis. The terminology remains influenced by biomicroscopy and fluorescein concepts. Different terms are used to name different conditions which have in common the presence of cystoid spaces, including foveal pseudo cyst, tractional cystoid cavity, occult outer macular hole, cystoid macular edema, tractional macular edema, foveoschisis, and outer retinal cavitation. In this lecture, we would like to point out the limits of our knowledge concerning the pathological intraretinal cavities as they are revealed by OCT.