The Optic Nerve Head Analyzer (Rodenstock München, FRG) was used to investigate the optic disc structure of 9 eyes before and after surgical reduction of intraocular pressure (IOP). Four out of 9 eyes showed a marked increase of their temporal neuroretinal rim area after surgery (between 140% and 400%). The observed increase of neuroretinal rim area was still present after more than one year, although it was less pronounced. Five eyes did not show changes of the neuroretinal rim area of their optic discs. A further evaluation regarding IOP and visual field of the 9 eyes examined lead to the following

Results: 1) There is no correlation between increase of neuroretinal rim area and extent of IOP reduction, i.e. some eyes showed an increase of neuroretinal rim area with only slight IOP reduction whereas others with more pronounced IOP reduction did not show an increase of neuroretinal rim area. 2) All eyes showing an increase of neuroretinal rim area after surgical IOP reduction had normal visual fields an a mean sensitivity of more than 24.5 dB within the central part of the G 1-program of the Octopus perimeter. 3) All eyes without increase of the neuroretinal rim area after surgical IOP reduction had visual field defects and a mean sensitivity of less than 19 dB within the central part of the G 1-program. According to these data we suppose that occurrance of increase of neuroretinal rim area after glaucoma surgery depends mainly on the stage of glaucoma (as determined by visual field testing) and that it is not clearly correlated to the amount of IOP reduction.