Morphological changes of the sensory retina following the occlusion of ciliary arteries in rabbits.

The whole retina, except for the medullary fiber zone in a rabbit eye, is supplied by choroidal circulation. Therefore, the histopathological changes of the sensory retina due to choroidal circulatory disturbance in rabbits may be comparable to that of the human sensory retina in the case of ophthalmic artery occlusion. This study was carried out to evaluate the histopathological changes of the ischemic retina secondary to the occlusion of choroidal circulation. The experimental occlusion of all posterior ciliary arteries and anterior ciliary arteries in the horizontal rectus muscle of rabbit eyes was performed and the subsequent histopathological changes of the sensory retina were observed by transmission electron microscopy. The morphological changes of the sensory retina following the occlusion of the ciliary arterial system are as follows: severe loss of the inner and outer segments of the photoreceptor, mild to moderate degeneration of the ganglion cells, and excellent preservation of the Müller's cell fibers and the extension of the cytoplasmic villous processes to the cytoplasmic vacuolar spaces of other degenerated cells. These findings indicate that the Müller's fibers in the ischemic condition of retina might contribute to the formation of gliosis or scarring of a damaged retina.