Tuesday, October 11, 2011
Ophthalmoscope permits direct inspection of the optic disc, the retina and the retinal vessels. Since arteries and arterioles in the eye may reflect the state of vessels of similar size elsewhere in the body, examination of the fund is an important procedure in the investigation of cardiovascular disease. In particular, very useful information as regards diagnosis and prognosis may be obtained in hypertension.
The optic discs should first be examined, after which the four quadrants in each eye should be studied and attention paid to the vessels and the presence or absence of absence of hemorrhages and exudates. The central retinal artery and its primary and secondary branches correspond in size to small arteries and are prone to atherosclerosis and consequently thrombosis. Thrombosis may also occur in the veins. Beyond the second bifurcation the vessels are arteriolar in the veins. Important vascular changes may occur in essential hypertension nephritis diabetes and eclipse, or as a result of degenerative arterial disease independent of such conditions. Hemorrhages and exudates result from rupture of capillary walls or from increase in their permeability. Papilloedema is due to transudation of fluid into the nerve head and occurs from a number of causes including severe hypertension.
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