Background:Although many investig ators have previously reported various ocular complications induced by vitrecto-my,little is known about post-opera tive morphological changes in the optic disc.The purpose of this study is to evaluate the effect of vitrectomy an d fluid-air(F-A)ex-change on the post-operative morphology of the optic disc.Methods:We examined 31eyes th at had undergone vitrectomy for macular holes(22eyes)or epiretinal membranes(9eyes).Only the patients with macular holes were treated by fluid-air exch ange.Morphological changes in the optic disc were evaluated using the Hei-delberg Retina Tomograph.Results:C /D area ratios significantly decreased for 6month s post-operatively.The rim volumes significantly increase d for 1month following surgery.Cup volumes significantly decreased at 3months after surgery.No significant change of mean cup depth was observed post-operatively.The eyes that had not been subjected to F-A exchange showed no s ignificant morpho-logical change following surgery.I n contrast,the eyes that had undergone F-A exchange showed significant decrease in C /D area ratio and cup volume and an increase in rim volume and mean cup depth for considerable periods following surgery.Any of the patien ts showed no post-operative visual field loss.Conclu sion:Whereas no vi-sual field loss is observed,vitrectomy with F-A exchange induces morphological changes in th e optic disc for sig-nificant periods following surgery. Background: Although many investig ators have previously reported various ocular complications induced by vitrecto-my, little is known about post-opera tive morphological changes in the optic disc. The purpose of this study is to evaluate the effect of vitrectomy an d fluid-air (FA) ex-change on the post-operative morphology of the optic disc. Methods: We examined 31 eyed th at had undergone vitrectomy for macular holes (22 eyes) or epiretinal membranes (9 eyes). Of the patients with macular holes were treated by fluid -air exch ange. Morphological changes in the optic disc were evaluated using the Hei-delberg Retina Tomograph. Results: C / D area rates significantly decreased for 6month s post-operatively. The rim volumes significantly increase d for 1month following surgery. Cup volumes significantly decreased at 3months after surgery. No significant change of mean cup depth was observed post-operatively. The eyes that had not been subjected to FA exchange showed no s ignificant morpho-logical change following surgery. I n contrast, the eyes that had undergone FA exchange showed significant decrease in C / D area ratio and cup volume and an increase in rim volume and mean cup depth for considerable periods following surgery. Any of the patien ts showed no post -operative visual field loss. Confluence: Whereas no vi-sual field loss is observed, vitrectomy with FA exchange induces morphological changes in th e optic disc for sig-nificant periods following surgery.