Abstract
Purpose: :
Diurnal intraocular pressure (IOP) evaluation is commonly performed to determine key parameters such as mean, peak and range of IOP. How well does a single-day IOP curve characterize diurnal IOP parameters on future days?
Methods: :
Post hoc analysis of prospectively collected data. Thirty-six healthy subjects underwent Goldmann tonometry at 0800, 1000, 1200, 1400, 1600 and 1800 hrs on five days: baseline and one week, one month, six months and twelve months later. Mean, peak and range of IOP were determined at each of the five visits. The coefficient of determination (r2) was calculated for the comparison of baseline values to each subsequent value.
Results: :
For mean IOP, the coefficients of determination comparing baseline to 1 week, 1, month, six months and 12 months ranged from 0.511-0.668. For peak IOP, the coefficients of determination comparing baseline to 1 week, 1, month, six months and 12 months ranged from 0.562-0.696. For range of IOP, the coefficients of determination comparing baseline to 1 week, 1, month, six months and 12 months ranged from 0.026-0.238.
Conclusions: :
Mean IOP and peak IOP determined by single-day diurnal IOP evaluation correlated modestly with mean and peak IOP on subsequent days. IOP range determined by single-day IOP evaluation correlated poorly with IOP range on subsequent days. Single-day diurnal IOP assessment may not fully characterize clinically relevant diurnal IOP parameters in healthy subjects.
Keywords: circadian rhythms • intraocular pressure