Abstract:

Objective To investigate the diurnal variation of intraocular pressure in patients with normal tension glaucoma. Methods Intraocular pressure was measured in 35 patients with normal tension glaucoma (70 eyes) by Goldmann applanation tonometer, at 4-hourly intervals for 2 d (2:00, 6:00, 10:00, 14:00, 18:00, 22:00, 24:00, 4:00, 8:00, 12:00, 16:00 and 20:00). The data were analyzed by the frequency, curve estimation and general linear model programs of SPSS11.0 software. Results Most patients with normal tension glaucoma had peak intraocular pressure at 12:00 (18.6%) and trough intraocular pressure at 24:00 (22.9%). The percentage of peak intraocular pressure outside clinic hours (8:00 to 16:00) in patients with normal tension glaucoma was 50%, and the amplitude of variance was 2.3 to 9.5 mmHg. There was a strong positive correlation in intraocular pressure between both eyes at each time point, and the diurnal curves of the right and left eyes had parallel profiles in patients with normal tension glaucoma. Conclusion Serial measurement of intraocular pressure can help to avoid the peak and trough intraocular pressure, and may benefit in the management of glaucoma.

Key words: intraocular pressure, diurnal variation, normal tension glaucoma