To compare the correlation of the fellow-eye's intraocular pressure (IOP) response in one-eye trials performed separately for each eye with that of bilateral treatment in normal subjects.
A one-eye trial with topical latanoprost applied once daily for 7 days was carried out in the right eye and then in the left eye of 41 normal subjects. Bilateral treatment was performed in a different set of 41 normal subjects. IOPs were measured at 3 time points on day 0 and on day 7.
Latanoprost significantly reduced IOP of treated eyes in one-eye trials (2.8±1.6 and 2.7±1.6 mm Hg in the first and second trial, respectively) and in bilateral treatments (2.8±1.3 and 2.6±1.4 mm Hg in the right and left eye, respectively). Correlation of mean diurnal IOP reduction between 2 one-eye trials was poor (r2=0.102), even after subtracting the nontreated eye IOP fluctuations from the treated eye IOPs (r2=0.097), but that between fellow eyes in bilateral treatment was excellent (r2=0.849). Correlation of baseline IOP at each time point between fellow eyes in one-eye trials and bilateral treatment (r2=0.729 to 0.949) was better than that in the same eye between 2 one-eye trials (r2=0.319 to 0.631).
Fellow eyes in normal subjects showed a symmetrical IOP response to short-term bilateral treatment with latanoprost, although they did not respond symmetrically to one-eye trials performed separately for each eye. Poor correlation of IOP changes between 2 one-eye trials may be caused by different IOP responsiveness to latanoprost at each trial, rather than asymmetrical IOP fluctuations.
Department of Ophthalmology and Visual Science, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
Financial Support: None.
Reprints: Tomomi Higashide, MD, PhD, Department of Ophthalmology and Visual Science, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, Ishikawa 9208641, Japan (e-mail: firstname.lastname@example.org).
Received for publication April 16, 2007; accepted August 5, 2007