Intraocular Pressure and Conjunctival Hyperaemia with Bimatoprost Every 48 Hours Versus Every 24 Hours

PurposeTo evaluate the efficacy and tolerability of a reduced rate of bimatoprost administration.MethodsDiurnal intraocular pressure (IOP) was recorded at 10 a.m., 2 p.m. and 6 p.m. in 40 eyes of twenty Caucasian patients (age range 56-75 years), with ocular hypertension or primary open angle glaucoma, at baseline and four weeks later. The right eye received daily bimatoprost, and in the left eye bimatoprost was administered every 48hours at 8 p.m. Bulbar conjunctival hyperaemia was assessed by direct observation by a masked observer at baseline and at week 4 and was graded as none, minimal, mild, or moderate or severe (0 to 4).ResultsBaseline mean diurnal IOP in the right eye significantly (P<0.001) decreased from 25.4±2.8 to 17.8±1.8mmHg 14 to 22hours after daily bimatoprost. Baseline mean diurnal IOP in the left eye significantly (P<0.001) decreased from 25.2±2.0 to 19.0±1.7mmHg 38 to 46hours post-dose. The reduction in the right eye was significantly greater than in the left (P=0.02). The average conjunctival hyperaemia after bimatoprost every 24 and 48hours was graded as 2.4±1.0 and 1.8±0.8 respectively and this difference was significant (P<0.01).ConclusionBimatoprost every 48hours was less effective than daily bimatoprost (24.6 vs. 30% IOP decrease), but caused less short term conjunctival hyperaemia. This off label dose schedule may be proposed to patients complaining of ocular redness especially in the first weeks of treatment