Lipaemia of the limbal vessels.

Abstract

A rise in the plasma triglycerides above a certain level imparts a milky opalescence to the plasma. This is termed lipaemia. Like other lipids the triglycerides are transported in the bloodstream within lipid-protein complexes, the plasma lipoproteins. Triglyceride of dietary origin is carried in the large lipoprotein particles called chylomicrons, while that synthesized within the body is carried in the pre-beta lipoprotein fraction of the plasma. An excess of either of these fractions is able to produce lipaemia (Rifkind, I970). Lactescence of the plasma in a specimen of withdrawn blood is sufficient to diagnose hypertriglyceridaemia and indicates the need for a full lipid analysis of the blood. However, hypertriglyceridaemia may also be diagnosed by clinical examination of the fundus oculi from the presence of lipaemia retinalis (Duke-Elder and Dobree, I967). In this situation the retinal arteries and veins become indistinguishable, assume a milky, pinkish colour, and lose their light reflex. When the lipaemia is of severe degree the fundus colour may lighten also; this is due to lipaemia of the choroidal vessels. A sufficiently raised triglyceride blood level, whatever its cause, may produce lipaemia, which has thus been seen with primary hyperlipoproteinaemia of Types I, III, IV, and V (Fredrickson, Levy, and Lees, I967), and in their secondary phenotypes (Vinger and Sachs, I970). The observation of lipaemia retinalis may therefore be the first indication of a significant disorder of lipoprotein metabolism. The present paper describes a new ocular sign of lipaemia observed in the vessels of the globe and limbus.