Retinal micro-aneurysms and punctate haemorrhages

Abstract

It can be shown that many, if not most, of the so-called punctate haemorrhages characteristically seen in diabetic retinopathy are actually capillary aneurysms. By examination of the unstained retina in bulk, as well as in - vertical and flat serial sections, these bodies are seen to be compact collections of red blood corpuscles, globular in form, and with an average diameter of 50 to 60 μ, enclosed tin a wall of varying thickness. With'few exceptions they occur in the inner nuclear layer, in the course of the capillaries which link the deeper and more superficial capillary plexuses of the retina.' They may be a source of haemorrhage by diapedesis or by rhexis, and many of them are seen to iundergio a process of thrombosis and cicatrisation. -They represent a stage in the vicious . circle in which changes in the capillary endothelium lead to a stasis in the.circulation whicji, in turn, causes further vascular changes, especially on the venous side of the retinal circulation.