Complications after modern filter operations in glaucoma.

As long as the indications and limitations of laser trabeculoplasty have not yet been established by follow-up over several years, conventional surgical filter operation will not be superfluous. The reduction of the complications brought about by introduction of the scleral flap technique is described. Apart from cicatricial obliteration of the filtering zone, bulbar hypotension due to overfiltration as well as to external fistula and above all the resulting ciliary body-choroid detachment still occurs after trephination with the scleral flap (goniotrephination, trabeculectomy). Attention is drawn to the tension of the scleral flap adapted to the normalized intraocular pressure and reliable preclusion of an external fistula by perfusion test at the end of the operation. The membrane formation probably deriving from the internal Tenon's capsule which leads to a 'pseudofiltering bleb' is discussed as a rare complication (1.5%) which is of basic interest.