Optic disc changes were studied in young and elderly glaucoma patients who underwent reduction of intraocular pressure (IOP) by filtrating surgery. A computerized videographic image analysis system (Optic Nerve Head Analyzer, Rodenstock) was used to measure the cup/disc-ratio, the ratio of the rim area over the disc area (rim area/disc area-ratio), and the ratio of the cup volume over the disc area (cup volume/disc area-ratio) before and after filtrating surgery. Each parameter was assessed as total and quadrantal values. Materials consisted of 19 eyes of 15 patients (8 eyes of 5 patients with primary open angle glaucoma, 2 eyes of 2 patients with secondary glaucoma, and 9 eyes of 7 patients with developmental glaucoma). Sixteen eyes (84%) of 12 patients showed a decrease of the total cup/disc-ratio after operation. In this group, the patients had a decrease in IOP of 18.9 +/- 10. 6mmHg (mean +/- SD) after the operation. Among 16 eyes that had a decreased total cup/disc-ratio, statistically significant decrease of the cup/disc-ratio (p less than 0.01) and statistically significant increase of the rim area/disc area-ratio (p less than 0.01) were noted in total and for all quadrants except for the temporal. The greatest improvement of cupping was seen in the nasal quadrant. With regard to cup volume/disc area-ratio, a statistically significant decrease was observed in total and in all quadrants (p less than 0.01). The IOP change correlated linearly with that of the total cup volume/disc area-ratio (R = 0.51, p less than 0.05). No statistically significant linear correlation was noted between age and the change in any disc parameter.