• Background: Until recently, there has been a paucity of quantitative evidence for intraocular pressure (IOP)-dependent optic disc cupping change in adult glaucoma patients. Therefore, we investigated the relationship between optic disc cupping change and IOP control. • Methods: The study involved 78 eyes of 78 randomly selected adult patients with early to moderate chronic open-angle glaucoma (COAG), treated on various therapeutic regimens, who had had two consecutive successful optic disc analyses with the Rodenstock Optic Nerve Head Analyzer 15.8 ± 14.8 weeks apart. • Results: The mean initial IOP of 27 eyes (34%) with cupping reversal did not differ from that of 17 eyes (22%) demonstrating progressive deterioration (29.2 ± 8.8 vs 26.2 ± 6.1 mmHg,P > 0.5), but the reversal group did have a significantly greater mean IOP decrease than the progression group (−10.8 ± 7.9 vs −1.0 ± 7.7 mmHg,P < 0.001) and significantly lower mean final IOP (18.3 ± 6.1 vs 25.2 ± 7.9 mmHg,P < 0.003). • Conclusion: A decrease of optic disc cupping is more likely with a greater IOP reduction and a lower final IOP, and an increase of cupping is more likely with less or no IOP reduction and a higher final IOP.