Comparative studies (trypsin digestion technique) on retinal capillary network of control and cardiomyopathic hamsters with congestive heart failure revealed foci of abnormal capillaries in edematous animals. The capillary tubes displayed variable diameters and irregular paths with loss or degeneration of their nuclei (endothelial cells and intramural pericytes). These changes, as demonstrated by marked increase in venous pressure, probably depended upon hypoxia associated with venous stasis. Quantitative evaluation of retinal capillary constituents revealed that in hamsters, as in man, density of capillaries varied with the distance from the papilla. Though slightly more frequent in cardiomyopathic animals, capillary bridges remained a function of the capillary density in both groups. The intramural pericyte-toendothelial cell ratio is less in hamsters than in other species.
Forthomme D, Cantin M, Bajusz E. Retinal Vascular Bed in Heart FailureStudy in Cardiomyopathic Hamsters. Arch Ophthalmol. 1973;89(2):128-137. doi:10.1001/archopht.1973.01000040130017