Venous pressure and ocular tension; data concerning the diurnal variation of ocular tension.

ATTENTION was first called to the diurnal changes of ocular tension by Maslenikow (1904). The aetiology of this physiological phenomenon is controversial. Kollner (1918) associated it with the arterial system, assuming that a sudden rise or fall in blood-pressure causes a corresponding change in ocular tension. But the diurnal variation of ocular tension cannot be related to blood-pressure, because the former is highest in the morning when the latter is lowest. Thomassen and others (1950) stated that a variation in the pressure in the episcleral veins precedes the diurnal variation of the ocular tension. Weinstein (1950, 1951) has demonstrated that pressure on the jugular vein holds up the circulation within the aqueous veins. At the Ophthalmic Department of the Szabolcs State Hospital, Budapest, we have investigated a possible co-ordination of the general venous pressure and the diurnal variation of the ocular tension, determining the former by the method of Groak (1938) on the cubital vein (normally up to 15 cm. water). Ciotola (1936a, b) and Benstein (1950), state that the pressure in the cubital vein is increased in cases of congestive glaucoma, but we were unable to confirm this statement by single determinations of the venous pres-