Abstract
Purpose: :
Our purpose was to study the effect of topical travoprost 0.004% on ocular blood flow in new, untreated open angle glaucoma and ocular hypertension patients.
Methods: :
27 new untreated open angle glaucoma and ocular hypertensive patients were prospectively recruited from our glaucoma clinics. Ocular blood flow was assessed in one eye in the morning before starting treatment and then in the morning following four weeks of daily treatment with topical travoprost 0.004% qhs. Optic nerve neuroretinal rim blood flow was measured using scanning laser Doppler flowmetry and SLDF software v3.3. Rim flow values were derived from the mean of five high quality images centred on the optic nerve head. Retinal blood flow was measured in the major infero–temporal retinal artery using the Canon Laser Blood Flowmeter which measures blood velocity and blood column diameter non–invasively.
Results: :
Mean IOP fell from 23.7 ± 4.5 to 16.5 ± 2.9 mmHg, a reduction of 30.3%, p=0.0000. Mean rim blood flow increased by 10.0%, from 194 ± 60au to 213 ± 61au, p=0.01. In OAG patients (n=15) mean rim flow increased from 180 ± 63au to 203 ± 61au, a change of 12.7% , p=0.0009, while it was virtually unchanged in OHT patients. In eyes with initial rim flow less than the median for the group, mean flow increased from 150 ± 37au to 184 ± 46au, a change of 22.6%, p=0.0005. Mean retinal blood flow increased non–significantly by 4% from 10.6 ± 4.9µl/min to 11.0 ± 4.6 µl/min, p=0.4. In OAG patients mean retinal flow decreased from 10.3 ± 5.2µl/min to 10.2 ± 4.4 µl/min, a change of 0.9 %, p=0.75. In eyes with initial retinal flow less than the median for the group, mean flow increased from 7.2 ± 1.8 µl/min to 7.6 ± 2.0 µl/min, a change of 5.5%, p=0.4.
Conclusions: :
Treatment with topical travoprost was associated with a significant increase in neuroretinal rim blood flow as measured by SLDF. Improvements in neuroretinal rim blood flow were greater in open angle glaucoma and in patients with lower flow prior to treatment. Retinal blood flow did not change significantly. These results also support the concept of defective optic nerve head vascular autoregulation in glaucoma.
Keywords: blood supply • clinical laboratory testing • intraocular pressure