7.5.5 Interpretation

The presence of a carotid bruit and/or weak or asymmetric carotid pulse with an ipsilateral ocular risk factor may be indicative of a potentially lifethreatening cerebrovascular or cardiovascular disease. Referral should be made for an appropriate medical assessment. Note that the absence of a carotid bruit does not however rule out carotid stenosis as the artery could be nearly entirely occluded, resulting in the absence of turbulent flow sounds. An evaluation of symptoms, ocular and other systemic risk factors should be considered when deciding on referral for further assessment.

7.5.6 Most common errors

1.Inter-observer variability is high with this procedure so practice is required to obtain reliable results.

2.Interpreting as abnormal a bruit found in children or young adults. These are a result of the vessel elasticity in this age group and are benign.

3.Producing an iatrogenic bruit by placing too much pressure on the artery. Moving the bell over the skin, moving your fingers on the chestpiece or breathing on the tubing can also produce confusing sounds.

4.If too much pressure is put on the common carotid when it is partially occluded with atherosclerotic plaque, the vessel could become mechanically occluded producing a transient ischaemic attack.

5.It may be difficult to palpate the pulse or detect flow sounds in a patient with excessive neck tissue.

6.Palpating the carotid artery for the pulse at the level of the carotid sinus may result in an increase in vagal tone and bradycardia which may be substantial enough to result in syncope.

7.6 BIBLIOGRAPHY AND

FURTHER READING

Casser, L., Fingeret, M. and Woodcombe, H.T. (1997) Atlas of primary eyecare procedures, 2nd edn. Norwalk: Appleton & Lange.

7.7 REFERENCES

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Chobanian, A.V., Bakris, G.L., Black, H.R. et al. (2003) Seventh report of the joint national committee on prevention, detection, evaluation and treatment of high blood pressure.

Hypertension 42, 1206–1252.

Conto, J.E. (1994) Cardiovascular disease. In:

Ocular manifestations of systemic disease (ed. B. Blaustein). New York: Churchill Livingstone.

Gardner, M. (1992) Basic anatomy of the head and neck. Philadelphia: Lea & Febiger, pp. 183–186.

Hurcomb, P., Wolffsohn, J. and Napper, G. (2001) Ocular signs of systemic hypertension: a review.

Ophthalmic and Physiological Optics 21, 430–440. Kikuya, M., Chonan, K., Imai, Y. et al. (2002)

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Lawrence, P.F. and Oderich, G.S. (2002) Ophthalmic finding as predictors of carotid artery disease. Vascular and Endovascular Surgery

36, 415–424.

Luo, B.P. and Brown, G.C. (2004) Update on the ocular manifestations of systemic arterial hypertension. Current Opinion in Ophthalmology

15, 203–210.

Lyons-Watt, V., Anderson, S., Townsend, J. et al. (2002) Ocular and systemic findings and their correlation with hemodynamically significant carotid artery stenosis: a retrospective study.

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(2004) Ocular findings as predictors of carotid artery occlusive disease: is carotid imaging justified? Journal of Vascular Surgery 40, 279–286.

O’Brien, E., Beevers, G. and Lip, G.Y. (2001) ABC of hypertension: blood pressure measurement.

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Sims, A.J., Reay, C.A., Bousfield, D.R. et al. (2005) Low-cost oscillometric non-invasive blood pressure monitors: device repeatability and device differences. Physiological Measurement 26, 441–445.

Wolffsohn, J.S., Napper, G.A., Ho, S.M. et al. (2001) Improving the description of the retinal

vasculature and patient history taking for monitoring systemic hypertension. Ophthalmic and Physiological Optics 21, 441–449.

Wong, W., Shiu, I., Hwong, T. et al. (2005) Reliability of automated blood pressure devices used by hypertensive patients. Journal of the Royal Society of Medicine 98, 111–113.

World Health Organization (2005) Affordable technology: blood pressure measuring devices for low resource settings. Geneva: WHO library.