[Circadian rhythm variations of intraocular pressure and therapeutic decisions: interpretation of clinical trial results based on a statistical model].

Therapeutic decisions (treatment initiation, continuation, change, combination, etc.) based on intraocular pressure (IOP) monitoring require knowledge of both circadian IOP fluctuations and the pharmacological circadian rhythm of the active ingredients. A simple model was applied to data from two clinical trials to estimate the consequences of circadian IOP fluctuations on (1) ocular hypertension diagnosis, (2) therapeutic adjustments, and (3) the daily cumulative effect of marginally low therapeutic differences. A grid for clinical interpretation of the average IOP differences is presented. The probability of an IOP that exceeds the target value for the diagnosis or therapy varied to a large extent throughout the day. IOP was higher in the morning than in the evening. The IOP variance (measured by standard deviation) was an important factor in decision-making, regardless of the IOP value itself. Regular IOP monitoring over the entire day allowed minimization of the time spent above a target value. IOP differences that seemed low when expressed in average values in therapeutic trials could have clinically significant consequences in the practitioner's decisions. The data presented suggest that ocular hypertension diagnosis and therapeutic decisions should be made early in the morning, at least for most patients. In any case, the time of the measurement should be considered in the therapeutic approach.
(Copyright 2004 Masson)