Influence of age, systemic blood pressure, smoking, and blood viscosity on orbital blood velocities.

Abstract

The influence of multiple systemic factors upon the blood velocities obtained from the orbital circulations was investigated. The velocities obtained by colour Doppler imaging from the ophthalmic artery, central retinal artery, and vein from 95 ophthalmologicaliy healthy volunteers were analysed. The effects of age, systemic blood pressure, and smoking habit were examined. In 24 volunteers blood viscosity was also measured and its relation with blood velocity assessed. Age was weakly negatively correlated with the blood velocities in the ophthalmic artery and weakly positively correlated with resistance to flow in the retinal circulation. Systolic blood pressure showed a positive correlation with the peak systolic velocities in the arteries while cigarette smoking was associated with lower ophthalmic artery velocities. Increased haematocrit and viscosity were positively correlated with resistance to flow proximal to the ophthalmic artery and red cell rigidity negatively correlated with the pulsatility of flow in the retinal vein. These results help to identify the roles of systemic conditions in the ocular circulation. The influence of blood viscosity on retinal venous flow may be relevant to the pathogenetic mechanisms of conditions such as central retinal vein occlusion. (BrJ Ophthalmol 1995; 79: 17-22) Colour Doppler imaging allows examination of the pulsatile velocity of blood in the orbital vessels'"3 and has been used in the investigation of a number of vascular ophthalmic disorders."9 Although the effects of posture3 and intraocular pressure5' 1 have been investigated, the effects of various systemic factors upon the blood velocities obtained by this technique are as yet unknown. In this study the influence of age, systemic blood pressure, smoking habit, and arteriopathy were examined in a control population to determine their effect on these haemodynamic variables.In addition, blood rheology, which may have a profound effect on the blood flow of the eye and has been implicated in number of ophthalmic vascular disorders"-'' was examined in a group of volunteers also examined by colour Doppler imaging. The relation between the rheology of the blood and its pulsatile velocities was therefore investigated and interpreted with reference to the pathogenesis of ocular diseases. Subjects and method SUBJECTSNinety five volunteers were examined to provide control data and consisted of staff of the ophthalmology or radiology department at the Western Infirmary Hospital, Glasgow and relatives of patients attending the ophthalmology outpatient department. The volunteers were asked for history of general medical and ocular conditions, drug usage. Smoking habit was recorded as one ofthe following: (1) Non-smoker, (2) ex-smoker, (3) smokes less than 20 cigarettes each day, (4) smokes at least 20 cigarettes each day, (5) pipe or cigar smoker.

Variations in ocular hemodynamics in patients with early and late glaucoma

“…Our data analysis should not have been biased by this factor since gender seems to make no difference in orbital blood-flow parameters (Williamson et al 1995). Intraocular pressure was significantly higher (pΩ 0.02) in early glaucoma (16.7∫3.1) than that in late glaucoma (13.6∫3.0) and in the control (14.3∫2.6).…”

Alterations of the tear film and ocular surface health in chronic smokers

“…Fume particles and noxious gases such as nicotine and carbon monoxide may influence the circulatory system by inducing profound vasospasm, platelet aggregation, or leading to oxidative damage to lipids, proteins, and cellular DNA. [2][3][4][5][6][7][8] Epidemiological data link cigarette smoking as a risk factor for many ophthalmological disorders including strabismus in offspring of pregnant smokers, anterior ischaemic optic neuropathy, age related macular degeneration, cataract, thyroid ophthalmopathy, primary open angle glaucoma, diabetic retinopathy, uveal melanoma, conjunctival intraepithelial neoplasia, ocular sarcoidosis, and development of dry eyes. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] The Beaver Dam Study related current active smoking and past history of smoking to a higher prevalence of dry eye disease.…”

Choroidal blood flow and arterial blood pressure

“…In a previous study it has been observed that age is weakly negatively correlated with blood velocities in the ophthalmic artery. 19 Moreover, we studied subjects with mild untreated hypertension, because any form of anti-hypertensive medication may affect ocular blood flow. [20][21][22] Finally, we focused on subjects with SBPr160 mmHg and DBFr100 mmHg based on the evidence that even mild hypertension may induce an additional risk for progression of diabetic retinopathy in patients with type 2 diabetes.…”