Diurnal variation of intraocular pressure has been the subject of considerable interest and speculation since Maslenikow1 first called attention to it in 1904. Many authors writing on this subject have suggested that exaggeration of the normal diurnal pressure fluctuation is characteristic of early chronic open-angle glaucoma. As recently pointed out by Leydhecker,2 however, there seems to be little agreement as to the upper limit of "normal" diurnal variation, the value cited by various authors ranging between 2 and 10 mm Hg (Table 1). Moreover, only a few authors have presented convincing evidence to substantiate their opinions.
The most pertinent study is that of Drance,3 who measured the intraocular pressure in 404 eyes without glaucoma in a general hospital, recording tensions with the Schiøtz tonometer at 6, 9, and 11:30 am, and 2, 5, and 10 pm during the day. Diurnal variation in these patients ranged from 0
de VENECIA G, DAVIS MD. Diurnal Variation of Intraocular Pressure in the Normal Eye. Arch Ophthalmol. 1963;69(6):752-757. doi:10.1001/archopht.1963.00960040758013