Is Intraocular Pressure (IOP) Monitoring Outside of Normal Office Hours Clinically Useful?

Abstract

Abstract: : Purpose:To determine if IOP monitoring outside of normal office hours adds clinically useful information. Methods: We reviewed the records of all glaucoma patients (treated) admitted for 24–hour (24h) IOP monitoring from Sep/2001 to Sep/2004. Applanation IOP was recorded in both eyes every 2 hours in the sitting position and at 6 am in the supine position. Peak and range of IOP measurements during office hours (7:00 am–4:30 pm) were compared with those during the 24h period for each patient. IOPs during 5 office visits prior to admission were recorded. Results: 32 patients (22 F, 10 M) with open angle glaucoma were enrolled (mean age 67.3±12.1 years). Mean 24h IOP for all eyes was 13.0±2.2 mmHg. Mean peak 24h IOP (16.8±3.2 mmHg) was significantly higher than peak office IOP (14.7±3.2 mmHg) (p<0.03). Difference between the 2 peaks was ≥ 2 mmHg in 43% and ≥ 4 mmHg in 19% of eyes. Peak IOP was recorded outside office hours in at least one eye in 22 (68%) patients; in 7 of these, peak IOP was recorded at the 6 am supine measurement. Mean IOP fluctuation during 24h monitoring (7 mmHg) was significantly greater than during office hours (4 mmHg) (p<0.0001). Peak 24h IOP was higher than the peak IOP noted during previous office visits in 60.9% of eyes. 24h IOP monitoring led to treatment change in 20 (62.5%) patients (trabeculectomy, 5; laser trabeculoplasty, 3; medication change, 12). Conclusions: In this group of glaucoma patients, 24–hour monitoring of IOP revealed higher peaks and wider fluctuation of IOP than found during typical office hours. 24–hour IOP monitoring may reveal a greater role for pressure–related risk for glaucomatous progression than previously suspected.

Keywords: intraocular pressure • circadian rhythms