The uniocular drug trial and second-eye response to glaucoma medications☆
Presented in part at: Association for Research in Vision and Ophthalmology meeting, May, 2002; Ft. Lauderdale.
Received 26 March 2003; accepted 14 August 2003.
Abstract
Purpose
To determine if the intraocular pressure (IOP) reduction observed in a uniocular trial correlates with the IOP reduction seen in the fellow eye when the same medication is then administered to the second eye of patients with glaucoma.
Study design
Observational case series.
Participants
Fifty-two patients with bilateral glaucoma.
Methods
Glaucoma patients underwent uniocular trials of various glaucoma medications, then subsequently received the same drug in the fellow eye. The IOP reduction observed in the first eye was compared with that observed in the second eye to determine correlation.
Main outcome measure
Intraocular pressure reduction in fellow-eye pairs.
Results
Intraocular pressure dropped a mean of 5.7±3.8 mmHg (mean ± standard deviation) in the first eye after a uniocular trial, and 2.8±3.3 mmHg in the second eye after bilateral use. Regression analysis demonstrated a poor correlation between first-eye and second-eye response to the same medication (r2 = 0.0174). To minimize possible contralateral IOP effects of first-eye therapy, a subset of 26 patients treated with latanoprost (which has little if any contralateral IOP effect, due to rapid systemic metabolism) was studied, with no improvement in correlation (r2 = −0.0023).
Conclusion
Uniocular trials of glaucoma medications do not adequately predict second-eye IOP responses to the same medications. If both eyes of a glaucoma patient require IOP reduction, one should not assume that magnitudes of response will be equal in both eyes. The effect of a given medicine must be assessed independently for each eye.
1Department of Ophthalmology, West Virginia University, Morgantown, West Virginia, USA
2Department of Ophthalmology, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA
3Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
Correspondence and reprint requests to Tony Realini, MD, West Virginia University, Box 9193, Morgantown, WV 26505, USA.
Supported in part by unrestricted grants from Research to Prevent Blindness, Inc., New York; the Pat and Willard Walker Eye Research Center, Little Rock; and the Lions Eye Research Foundation of New Jersey.
ABSTRACT