The Efficacy of a Monocular Drug Trial in Normal-Tension Glaucoma

PURPOSE To evaluate the efficacy of a monocular drug trial in eyes with normal-tension glaucoma (NTG). METHODS This prospective study enrolled 74 patients with NTG. The monocular drug trial was started using latanoprost 0.005% for one week. If the intraocular pressure (IOP) reduction was greater than 15%, the same medication was administered to both eyes for one month. The unadjusted change and adjusted change (the change in the treated eye minus the change in the contralateral eye) in IOP were evaluated, and the predictors of IOP response were analyzed by multivariate linear regression. RESULTS Among the initial 74 patients, 31 (41.9%) were included; others were excluded because they did not meet the requisite conditions. The most significant predictors of IOP response in the initial eye and subsequent eye were the baseline IOPs in both eyes (β = 0.907, 0.771, respectively). The adjusted change in IOP of the initial eye had greater association (β = 0.589) with the IOP after monocular trial in the initial eye than that of unadjusted IOP change (β = 0.279). The adjusted change in IOP also had greater predictability (β = 0.348) for IOP after monocular trial in the subsequent eye than that of the unadjusted IOP change (β = 0.090). CONCLUSIONS Although the monocular trial in NTG patients had limited efficacy due to its stringent conditions, it was useful for evaluating the IOP response in the initial eye and for predicting the IOP response in the subsequent eye.