The objective of the prospective randomized study is to evaluate the effect of surgery of an idiopathic macular hole (IMH) on intraocular pressure (IOP). The study comprised 60 primary pars plana vitrectomies (PPV) on account of IMH using 16% perfluoropropane (C3F8). Stage III according to Gass predominated in 65% and stage IV in 28.3%. Furthermore the authors enlisted in the study 15 secondary PPV on account of a patent IMH. A total of 75 primary and secondary PPV were performed. In 43 PPV an autologous thrombocyte concentrate (ATC) was used. With regard to the IOP after PPV the patients were subdivided into the following groups. Group A: IOP under 24 mm Hg was recorded throughout the investigation period in 24 of 75 PPV (32%). The total mean value of IOP in group A was 17.4 mm Hg. Group B: Early increase of IOP during the first week after surgery was recorded in 51 of 75 PPV (68.0%) This group was divided into two sub-groups according to the maximum postoperative deviation of IOP during that period.Sub-group B1 comprised a total of 34 PPV (45.3%) where the maximum postope- rative deviation of IOP was between 25-35 mm Hg. The total mean value of IOP in sub-group B1 was 23.5 mm Hg. In sub-group B2 there was a total of 17 PPV (22.7%) and the maximum postopera- tive deviation of IOP was above 35 mm Hg. The total mean value of IOP in sub-group B2 was 28.6 mm Hg. Moreover the authors investigated the effect of ATC administration on the IOP after primary and secondary PPV. They did not reveal a significant relationship between administration of ATC and postoperative glaucoma. Conclusion: 1. Glaucoma after PPV in IMH can in indvidual cases cause deterioration of the functional results of the operation. PPV in IMH has an increased risk: a) in a monoculus, b) in advanced primary glaucoma with an open angle, c) in primary glaucoma with a narrow angle.

        Key words: idiopathic macular hole, pars plana vitrectomy, glaucoma