A Correlation Between Latanoprost-induced Conjunctival Hyperemia and Intraocular Pressure-lowering Effect

PURPOSE: To study any correlation between a short-term change in conjunctival hyperemia severity and the intraocular pressure-lowering effect induced by latanoprost. PATIENTS AND METHODS: A 114 patients (56 females and 58 males) with open-angle glaucoma or ocular hypertension were studied. Their mean age was 60.9±15.0 years (range, 25 to 87 y). The primary outcome measure was the change in conjunctival hyperemia grade at 2 days and the change in intraocular pressure at 6 months after the start of latanoprost administration. RESULTS: Mean intraocular pressure before and 6 months after latanoprost administration was 22.5±3.8 mm Hg and 16.5±2.9 mm Hg, respectively (P<0.0001). Mean conjunctival hyperemia grade before and 2 days after the administration of latanoprost was 0.32±0.58 and 1.74±1.11, respectively (P<0.0001). Mean change in intraocular pressure was -1.7±1.2 mm Hg (-6.6±5.1%) in eyes with no hyperemia grade change, -5.2±2.2 mm Hg (-21.5±7.6%) in eyes with a hyperemia grade change of 1, -7.3±2.8 mm Hg (-32.0±8.9%) in eyes with a change of 2, and -10.8±2.7 mm Hg (-46.1±8.6%) in eyes with a change of 3 or 4 (P<0.0001). There was a significant correlation between intraocular pressure change and hyperemia grade change (intraocular pressure: r=0.535, P=0.0001; percent of intraocular pressure: r=0.755, P=0.0001). CONCLUSION: A statistically significant correlation was found between a change in intraocular pressure and conjunctival hyperemia severity induced by latanoprost.