Externally applied corticosteroids increase the intraocular pressure in one-third of the general population. We evaluated the intraocular pressure in 62 patients with endogenously elevated serum cortisol levels due to hypothalamic pituitary-dependent Cushing's disease. All patients underwent transphenoidal microsurgical sella exploration within 4 years after the onset of subjective symptoms. The intraocular pressure (preoperative mean, 14.9 ± 3.5 mm Hg) exceeded 21 mm Hg in four eyes before surgery and in one eye after surgery (postoperative mean, 14.3 ± 2.8 mm Hg). In patients attaining postoperative remission and whose pressure readings were taken at least 3 months after surgery, the postoperative intraocular pressure was significantly (P=0.04) lower than that measured preoperatively (14.2±2.7 vs 13.0 ±2.0 mm Hg). Biomorphometry of the optic disc topography and the retinal nerve-fiber layer in 19 patients revealed no glaucomatous changes. In contrast to topically applied corticosteroids, endogenously elevated serum cortisol levels in patients with hypothalamic pituitary-dependent Cushing's disease increased intraocular pressure only slightly, with no great risk of glaucomatous optic nerve damage. © 1990 Springer-Verlag.