Choroidal innervation and optic neuropathy in macacque monkeys with laser- or anterior chamber perfusion-induced short-term elevation of intraocular pressure

Long-term intraocular pressure (IOP) elevation leads to a significant reduction of the intrinsic choroidal innervation and axon loss in the optic nerve. In this study we investigated early changes in these tissues in order to clarify the putative sequence of events between choroidal ganglion cell loss and optic nerve axon loss in 19 monkeys with experimentally induced glaucoma. After 1 month of increased IOP, severe optic neuropathy but no reduction of choroidal ganglion cells (CGC) was detectable. Beginning at 2 months after treatment signs of degeneration in CGC morphology were observed. Laser treatment of the trabecular meshwork without IOP elevation caused no changes in choroidal innervation. Our results show that there is no apparent association between reduction of CGC and optic neuropathy in the early stages of IOP elevation.