Abstract
Abstract: :
Purpose: To study the histopathological changes in the optic nerve following posterior insertion of a glaucoma drainage device. Methods: The Ahmed glaucoma valve (AGV) (model no.S-3 )was inserted 10-12 mm behind the limbus in the superotemporal quadrant of the rabbit eye. One eye of six albinos New Zealand rabbits was randomly assigned to the AGV group. At the end of two months, the enucleated eyes were examined histologically for optic nerve changes Results: The fibrous capsule around the endplates involved the optic nerve in all eyes in the AGV group. The endplate was found to be either in contact (4 eyes) or within 1 mm from the optic nerve (2 eyes) in all the six eyes. Histopathological examination of the optic nerves in the AGV group exhibited microglial loss, astrocyte clustering and fibrillary changes. No such changes were noticed in the control eyes. Conclusions: Posterior insertion of the AGV could lead to optic nerve damage secondary to compression or vascular compromise. The end-plate of the Ahmed glaucoma drainage device should be inserted 7-8 mm from the limbus rather than 8-10 mm as is currently recommended, to avoid the possibility of compressive optic nerve damage.
Keywords: animal model • pathology: experimental • anatomy