Intraocular pressure is intra- and interindividually inconstant. It is influenced by numerous ocular and general factors. We evaluated the question as to whether a short-term increase in intraocular pressure might change the two-dimensional topography of the optic nerve head. Optic disc photographs of 63 glaucomatous eyes in 33 Caucasian patients and 39 normal eyes in 22 subjects were taken at a baseline intraocular pressure of less than 20 mm Hg and at 1 and 8 s after pressure elevations of 10 and 20 mm Hg. No significant differences in the size and form of the optic disc, optic cup, neuroretinal rim, peripapillary scleral ring or parapapillary chorioretinal atrophy were found. The retinal vessels mostly reacted to the intraocular pressure elevation by an initial decrease and subsequent re-increase in their diameter; this change was significant (P less than 0.05) for the pressure elevation of 20 mm Hg. We conclude that the two-dimensional optic disc topography is not significantly changed by a short-term increase in intraocular pressure.