FLUCTUATIONS OF INTRAOCULAR-PRESSURE DURING THE DAY IN OPEN-ANGLE GLAUCOMA, NORMAL-TENSION GLAUCOMA AND NORMAL SUBJECTS

Purpose: The aim of the present paper is to describe the variations in intraocular pressure (IOP) during the day in normals, in patients wit h primary open-angle glaucoma (POAG) and in patients with normal-tensi on glaucoma (NTG). IOP represents one of the most important risk facto rs for glaucoma. However the IOP value is not constant during the day and IOP fluctuation could influence the diagnostic and prognostic eval uation of the glaucomatous disease. Methods: For this purpose IOP was evaluated every 2 h from 8 a.m. to 8 p.m. in one randomized eye of 33 normal subjects, 95 POAG and 50 NTG patients. Results: The results sho w that the highest IOP values were detectable in the morning in all th ree groups. The lowest values were found in the early afternoon hours. These variations were most evident in POAG patients. The daily IOP fl uctuations were directly proportional to IOP level. Conclusion: The st udy evidents that a single tonometric evaluation, especially if done i n the first hours of the afternoon, is not sufficient to correctly eva luate the IOP-related risk in glaucoma patients. If the pressure peaks are important in determining the extent of glaucomatous damage in NTG patients IOP should not have an important role in optic nerve head da mage. The use of diurnal curves seems to be mandatory for the assessme nt of IOP-related risk and of efficiency of the therapeutic approach.