Six cases of reversal of cupping have been collected in 28- to 62-year-old patients with open angle glaucoma. Reversal of cupping occurred after filtration surgery in five of the cases and after resolution of a glaucomatocyclitic crisis in one. The average intraocular pressure reduction was 27.5 mm Hg (a 68% fall). Reversal of cupping preponderantly consisted of a reduction in saucerization and undermining of the cup wall. An omnidirectional decrease in cup size resulted. A slight improvement in the visual field occurred in one eye after reversal of cupping. The most likely mechanism to explain reversal of cupping is a reduction in the posterior bowing of the lamina cribrosa and a reduction of scleral canal diameter after normalization of IOP. A distinction between true reversal of cupping and pseudoreversal (caused by disc edema from hypotony) could be made from studying the caliber of the large retinal veins. Treatment of early glaucoma, at which stage reversal of cupping is possible, is suggested.