Inner retinal ischaemia: current understanding and needs for further investigations.

Inner retinal ischaemia is involved in the pathogenesis of major vision-threatening diseases such as retinal vein thrombosis, diabetic retinopathy and retinopathy of prematurity. However, the pathogenesis of inner retinal ischaemia has not been fully elucidated, which represents an impediment to the development and improvement of techniques to prevent and treat these diseases on a rational basis. This paper provides a comprehensive review of current knowledge of the pathophysiology of inner retinal ischaemia, including clinical, anatomical and physiological aspects of disease development. It is suggested that chronic inner retinal ischaemia caused by capillary occlusion may develop secondary to an increase in hydrostatic pressure in the vessels. Further knowledge of the pathophysiology of inner retinal ischaemia can be obtained by identifying the mechanisms that lead to increased hydrostatic pressure in the capillary bed and establishing the structural and functional basis for the different response patterns in the central and peripheral areas of the retina that develop secondary to this increased hydrostatic pressure. Further elucidation of these unknown response patterns requires both in vitro and in vivo studies of retinal vascular pathophysiology. It is conceivable that a more detailed knowledge of these response patterns may help in the design of new treatments for retinal ischaemia and its vision-threatening consequences.