Diurnal intraocular pressure in untreated exfoliation and primary open-angle glaucoma

To describe and compare the diurnal intraocular pressure (IOP) variation in patients with exfoliation glaucoma (EXG) and primary open-angle glaucoma (POAG).

We prospectively investigated consecutive Greek patients with newly diagnosed untreated EXG and POAG. All patients were admitted to our ophthalmology department for 24-hour IOP measurements according to a standard protocol. After matching for age, we compared 40 pairs of patients with these 2 glaucomas.

Patients with EXG showed a significantly higher mean range of IOP (13.5 vs 8.5 mm Hg for POAG; unpaired t test, P < .001), higher maximum IOP (mean, 38.2 vs 26.9 mm Hg for POAG; unpaired t test, P < .001), and higher minimum IOP (mean, 24.7 vs 18.4 mm Hg for POAG; unpaired t test, P < .001) Patients with EXG more often demonstrated an IOP range higher than 15 mm Hg (35% vs only 7.5% for POAG). Importantly, in 45% of patients with EXG and 22.5% of patients with POAG, the peak level of IOP was found outside office hours. There was no significant difference in visual function (visual acuity, cupping, visual field) at diagnosis between the 2 glaucoma groups.

Significant fluctuation in the diurnal curve of the IOP distinguishes EXG from POAG and may be an important factor in predicting any subsequent poor response to medical therapy.