Reappraisal of biomicroscopic classification of stages of development of a macular hole.

PURPOSE To update the biomicroscopic classification and anatomic interpretations of the stages of development of age-related macular hole and provide explanations for the remarkable recovery of visual acuity that occurs in some patients after vitreous surgery. METHODS Recent biomicroscopic observations of various stages of macular holes are used to postulate new anatomic explanations for these stages. RESULTS Biomicroscopic observations include the following: (1) the change from a yellow spot (stage 1-A) to a yellow ring (stage 1-B) during the early stages of foveal detachment is unique to patients at risk of macular hole; (2) the prehole opacity with a small stage 2 hole may be larger than the hole diameter; and (3) the opacity resembling an operculum that accompanies macular holes is indistinguishable from a pseudo-operculum found in otherwise normal fellow eyes. CONCLUSIONS The change from a yellow spot (stage 1-A) to a yellow ring (stage 1-B) is caused primarily by centrifugal displacement of retinal receptors after a dehiscence at the umbo. The hole may be hidden by semiopaque contracted prefoveolar vitreous cortex bridging the yellow ring (stage 1-B occult hole). Stage 1-B occult holes become manifest (stage 2 holes) either after early separation of the contracted prefoveolar vitreous cortex from the retina surrounding a small hole or as an eccentric can-opener-like tear in the contracted prefoveolar vitreous cortex, at the edge of larger stage 2 holes. Most prehole opacities probably contain no retinal receptors (pseudo-opercula). Surgical reattachment of the retina surrounding the hole and centripetal movement of the foveolar retina induced by gliosis may restore foveal anatomy and function to near normal.