Glaucoma Research Today is a free monthly online journal that collates and summarizes the latest research about Glaucoma, including details on cataracts, surgery, treatment, blindness.

Diurnal fluctuation and concordance of intraocular pressure in glaucoma suspects and normal tension glaucoma patients.

Shuba LM, Doan AP, Maley MK, Zimmerman MB, Dinn RB, Greenlee EC, Alward WL, Kwon YH

Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.

PURPOSE: The study objective was to determine the concordance of intraocular pressure (IOP) in glaucoma suspects (GS) and normal tension glaucoma (NTG) patients. METHODS: This was a retrospective review of diurnal curves of untreated GS and NTG patients. No subject had IOP greater than 21 mm Hg. We defined GS patients as having suspicious optic nerves with normal visual fields, and NTG patients as having glaucomatous optic nerves with associated visual field loss. Goldmann applanation tonometry was performed at 10:00, 13:00, 16:00, 19:00, 22:00, and 07:00. Linear association of OD and OS IOP was estimated using Pearson correlation coefficient (r). The diurnal period was divided into 7 time intervals of 3, 6, 9, 12, 15, 18, and 21 hours, and the absolute difference in change in IOP between fellow eyes and probability that it was within 3 mm Hg were calculated. RESULTS: The study included 68 GS and 95 NTG subjects. The diurnal curves of the OD and OS showed a parallel course in both groups. The average correlations (r) of OD and OS IOP over the 6 time points were 0.78 and 0.81 for GS and NTG, respectively. The mean absolute difference in IOP change between OD and OS over the 6 time intervals ranged between 1.4 and 1.9 mm Hg for GS, and 1.3 and 1.5 mm Hg for NTG subjects. The probability that this difference was within 3 mm Hg ranged between 87% and 94% for GS, and 86% and 93% for NTG subjects. CONCLUSIONS: The diurnal variation in IOP between the 2 eyes in GS and NTG is largely concordant in approximately 90% of the time.

Published 17 April 2007 in J Glaucoma, 16(3): 307-12.
Full-text of this article is available online (may require subscription).

© 2005-2008 Glaucoma Research Today. All Rights Reserved.