Abstract
Purpose: :
Lowering intraocular pressure (IOP) with various topical drugs is thought to reduce the IOP fluctuation observed in clinical practice. The present study determined whether or not the 24-hour IOP fluctuation can be reduced by monotherapy of topical prostaglandin analog (latanoprost or travoprost) or beta-blocker (timolol).
Methods: :
We reviewed the 24-hour IOP data collected in a sleep laboratory from experimental subjects (age, 40-80 years) before and after receiving at least 4 weeks of latanoprost (N=18), travoprost (N=17), or timolol (N=17). Latanoprost or travoprost was given once daily before bedtime and timolol (Timoptic-XE) once daily in the morning after awakening. Measurements of IOP were taken every 2 hours sitting during the diurnal period (7 AM to 11 PM) and supine during the nocturnal period (11 PM to 7 AM) using a pneumatonometer. Fluctuations of IOP (peaks minus troughs) in the right eyes during the office-hour (9:30 AM, 11:30 AM, 1:30 PM, and 3:30 PM), diurnal, nocturnal, and 24-hour periods before (untreated baseline) and after the monotherapy were compared using the paired t-test.
Results: :
The baseline IOP fluctuations during the office-hour, diurnal, nocturnal, and 24-hour periods were in the range of 3.26-4.19 mmHg, 6.35-7.12 mmHg, 3.86-5.35 mmHg, and 8.97-10.38 mmHg, respectively. Monotherapy of latanoprost and travoprost had no significant effect on the IOP fluctuations during these time periods (P>0.05). Timolol monotherapy caused significant reductions of IOP fluctuation during the office-hour period (P<0.01) and the diurnal period (P<0.01), but it had no significant effect during the nocturnal period (P=0.917) or the 24-hour period (P=0.367). All three treatments of latanoprost, travoprost, and timolol reduced the 24-hour IOP means.
Conclusions: :
Prostaglandin analog monotherapy had no significant impact on the 24-hour IOP fluctuation in habitual body positions. Although timolol monotherapy caused a significant reduction of IOP fluctuation outside the nocturnal period, it had no significant effect on the 24-hour IOP fluctuation.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: risk factor assessment • circadian rhythms