Correlative 24-hour relationships between intraocular pressure and plasma cortisol in normal subjects and patients with glaucoma.

It has been known for many years that there is a 24-hour cycle of intraocular pressure (IOP) in normal subjects and in patients with glaucoma (Boyd and McLeod, i964; Drance, i963; DukeElder, I952; Ericson, 1958; Katavisto, I964; Langley and Swanljung, 195I; Maslenikow, 1904; Thiel, 1925). On the basis of infrequent measurements (generally two to four times per day), the highest pressures have been found in the morning upon awakening and the lowest values in the evening. In a recent report, we described the 24-hour pattern of IOP in normal subjects and in patients with glaucoma with measurements made hourly and, in some cases, every 20 minutes (Henkind, Leitman, and Weitzman, 1973). It was found that the lowest ocular tension occurred between 2 and 4 am, with the subsequent rise taking place during the latter third of the night's sleep period. It has been reported that adrenocorticoids may play a role in the pathogenesis of certain types of glaucoma (Armaly, I963; Becker, I967; Bernstein and Schwartz, I962). The plasma concentration of cortisol in man has also been shown to be at its lowest value during the early part of the nocturnal sleep period and to rise in an episodic manner during the latter half of the night (Boyd and McLeod, I964; Hellman, Nakada, Curti, Weitzman, Kream, Roffwarg, Ellman, Fukushima, and Gallager, 1970; Smith, Stempfel, Campell, Hudnel, and Richman, i962; Weitzman, Schaumburg, and Fishbein, i966). We have, therefore, carried out a study correlating the detailed 24-hour temporal relations between IOP and the episodic pattern of cortisol secretion in normal subjects and in patients with different types of glaucoma.