PT  - JOURNAL ARTICLE
AU  - Rotchford, Alan P
AU  - Uppal, Samreen
AU  - Lakshmanan, Arun
AU  - King, Anthony J
TI  - Day-to-day variability in intraocular pressure in glaucoma and ocular hypertension
AID  - 10.1136/bjophthalmol-2011-301266
DP  - 2012 Jul 01
TA  - British Journal of Ophthalmology
PG  - 967--970
VI  - 96
IP  - 7
4099  - http://bjo.bmj.com/content/96/7/967.short
4100  - http://bjo.bmj.com/content/96/7/967.full
SO  - Br J Ophthalmol2012 Jul 01; 96
AB  - Aims To investigate the day-to-day repeatability of intraocular pressure (IOP) measurements.Methods A prospective cohort study of untreated patients presenting with primary open-angle glaucoma or ocular hypertension presenting with IOP>21 mm Hg. IOP was measured by masked Goldmann tonometry at 08:00, 11:00 and 16:00 at each of the three weekly visits. After starting travaprost (0.004%) to both eyes, the measurements were repeated for a further three weekly visits. Day-to-day repeatability was estimated before and after commencing medication and reported as the coefficient of repeatability and coefficient of variability.Results At the 8:00 time point, mean IOPs were 26.1 and 17.9 mm Hg in the eye with higher pressure before and after starting treatment, respectively. Coefficient of repeatability and coefficient of variability were 6.8 mm Hg and 10.0%, respectively, before treatment, and 4.6 mm Hg and 10.5% on treatment. Therefore, before treatment and after starting medication the IOP lay within a range of ±20% of the mean IOP with 95% confidence.Conclusions The non-therapeutic variability from day to day significantly undermines the precision of IOP estimation and of the estimation of medication effectiveness even when the time of day is standardised in patients with primary open-angle glaucoma/ocular hypertension.