Effect of Treating Systemic Hypertension on Optic Nerve Head and Retinal Blood Flow

Abstract

Abstract: : Purpose: We evaluated the effect of treating systemic arterial hypertension on the blood flow of the optic nerve head neuroretinal rim and the peripapillary retina in relationship to atherosclerosis risk factors. Methods: 40 patients with systemic high blood pressure underwent Scanning Laser Doppler Flowmetry (SLDF,analysis software v3.3) before and at least 3 weeks after the normalization of blood pressure levels with systemic antihypertensive medications, as prescribed by a family medicine clinic. Each patient was classified into one of four groups (1=low, 2=mild, 3=moderate, 4=high) depending on the presence of risk factors as follows: duration of hypertension, diabetes, dyslipidemia and smoking. Results: The cohort of 40 patients had a mean arterial blood pressure decrease after treatment of 24 mmHg (118.7 +–9.8 to 94.7 +–5.9; p=0.000). The mean neuroretinal blood flow increased significantly (217.9+– 50au to 237.4+– 66au; p=0.009). Mean temporal and nasal retinal blood flow did not change significantly (p=0.735 and p=0.513). For group 1 (lowest risk for atherosclerosis, n=17) the neuroretinal rim blood flow increased significantly (from 214.3+–53.2au to 243.5 +–59.7au; p=0.001 ) while the retinal blood flow was unchanged (p=0.687 and p=0.572). Groups with greater risk factors did not show a statistically significant blood flow change. In the group of smokers (n=8) the mean neuroretinal rim blood flow decreased (from 221.2+–51.2au to 212.3+–68.7 au; p=0.696) while it increased in the non–smokers group (n=32) (from 217.1+–50.5au to 243.7+–64.9au; p=0.000); this difference between the two groups was statistically significant (repeated ANOVA p=0.044). Conclusions: Following normalization of systemic blood pressure, the neuroretinal rim blood flow increases in patients at low risk for atherosclerosis. The peripapillary retinal blood flow did not change significantly. In patients at high risk for atherosclerosis, particularly smokers, no significant change in neuroretinal rim blood flow was observed.

Keywords: optic flow • optic disc • blood supply