A 63-year old man, with a large central vitreous floater, underwent a Nd:YAG laser posterior hyaloidotomy. Although the vitreous floater disappeared from the central optical axis, visual acuity did not improve. Microperimetry performed with the SLO revealed an absolute scotoma, which corresponded well in shape and dimension with the original vitreous floater. This finding suggests that a fragment of the neurosensory retina became detached together with the internal limiting membrane in the process of the vitreous collapse.