Scanning laser Doppler flowmetry in glaucoma

Scanning laser Doppler flowmetry is a new means for the measurement of capillary perfusion. We studied the retinal and neuroretinal rim capillary perfusion with the Heidelberg Retina Flowmeter in one randomly selected eye of 31 healthy volunteers, 42 primary open angle glaucoma (POAG) patients and 17 normal pressure glaucoma (NPG) patients. The reproducibility of the measurements on the temporal and nasal retina and on the disc rim was 19%, 26% and 28% in the unselected control group, 12% in the POAG and 12%, 13% and 10% in the NPG group, respectively. Optic disc flow was significantly higher than retinal flow (p < 0.000001). Differences in corresponding flow values between healthy volunteers and glaucoma patients as well as between POAG and NPG patients were not statistically significant. There was no correlation between the temporal and nasal flow values of the same eyes. The average variation in flow between adjacent frame positions was 18.5%. Actual intraocular pressure and the type of treatment had no influence on the retinal flow. The results suggest that the position of the test-frame is very important for the final result. We could not find any significant difference in the perfusion between glaucomatous and control eyes with the Heidelberg Retina Flowmeter.