Reduced intraocular pressure and increased ocular perfusion pressure in normal tension glaucoma: A review of short-term studies with three dose regimens of latanoprost treatment

Currently used ocular hypotensive agents do not effectively lower intraocular pressure (IOP) in some normal-tension glaucoma (NTG) patients. The prostaglandin F-2 alpha analogue, latanoprost, has been shown to reduce IOP in normal subjects and ocular hypertensive glaucoma patients by increasing uveoscleral outflow. This mechanism is expected to be particularly effective in the lower IOP range that is typical of NTG. To date, three dose regimens of latanoprost have been shown to reduce IOP significantly in NTG. The IOP reductions of 14.2% and 15% obtained with twice-daily application of 0.0015% and 0.006% latanoprost, respectively, were comparable to the modest IOP reduction that has been reported for other glaucoma drugs in NTG. In contrast, once-daily application of 0.005% latanoprost resulted in a 21.4% IOP reduction. In another study that included 24-hour monitoring of systemic blood pressure and heart rate in NTG patients, the ocular perfusion pressure was found to improve more on once-daily 0.005% latanoprost than on twice-daily treatment with 0.5% timolol. Thus, once-daily 0.005% latanoprost appears to be a more effective and more convenient ocular hypotensive agent for treating NTG than currently used glaucoma drugs. However, long-term studies will ultimately be needed to establish the efficacy of this new drug to delay or prevent the progression of visual field loss in normal tension glaucoma.