Intraocular Pressure Lowering Effect of Latanoprost as First-line Treatment for Glaucoma

PURPOSE: The purpose of this study was to assess the intraocular pressure (IOP) - reducing effect of latanoprost in treatment-naïve patients with newly detected open-angle glaucoma with no restriction of the level of untreated IOP. METHODS: Eighty-six patients (105 eyes) with a diagnosis of open-angle glaucoma received IOP-lowering therapy with latanoprost. The IOP reduction 1 and 3 months after initiation of treatment was recorded. RESULTS: Mean untreated IOP for all eyes was 26.2 mm Hg (ranging from 10 to 51 mm Hg). The mean pressure reduction was 7.9 mm Hg (28%), with equivalent average levels at 1 and 3 months. The reduction in IOP ranged from -2.3 to 25.3 mm Hg after 1 month, and from -1.3 to 33.3 mm Hg after 3 months. The pressure-lowering effect was considerably more pronounced in eyes with higher untreated IOP; the reduction increased by 0.55 mm Hg per mm Hg higher untreated IOP. Four eyes, with untreated IOP within statistically normal limits, had no or negative IOP-reduction. A regression model predicted that IOP reduction ended at untreated IOP≤16 mm Hg. Multiple regression analysis showed that an additional IOP-lowering effect of 1.28 mm Hg was achieved in eyes with pseudoexfoliation glaucoma. CONCLUSIONS: To the best of our knowledge, this paper is the first to report the IOP-reducing effect of latanoprost treatment at all untreated IOP levels in newly detected glaucoma patients. The effect was proportional to the untreated IOP at all levels above 16 mm Hg and better at higher untreated IOP levels, also in relative terms. Our results further confirm the indication of latanoprost as a first-line therapy for glaucoma.