The aim of the study is to assess the benefits and limits of intraoperative OCT (i-OCT), for example whether I-OCT assisted membrane peeling is possible without use of dyes for enabling better localistion of the ERM during surgery and to compare that scheme with different "gold standard" dyes for peeling such as membrane blue dual and triamcinolone. Rationale for that study is to work out which setting enables best visualisation of ERM and ILM in i-OCT. A limitation of that method seems to be visualisation of the inner limiting membrane (ILM), so that dying of the ILM will probably be still necessary in all cases where ILM-peeling is sheduled.