How much is the brain involved in glaucoma?

Should glaucoma specialists turn some of their attention towards the brain instead of the eye? The question is a reasonable one, as emphasised by a case report in this issue of BJO (p 674). Gupta et al present the autopsy findings from a case with bilateral open angle glaucoma with severe visual field loss in both eyes. Their main finding was a neural degeneration engaging all parts of the central visual pathways, from the intracranial optic nerves to the visual cortex. Neurons in the lateral geniculate nucleus (LGN) were smaller and had smaller nuclei compared to controls. The changes affected both the magnocellular and parvocellular layers of the LGN but were slightly more pronounced in the magnocellular layers.

These findings resemble those previously reported from studies on experimental glaucoma in monkeys.1,2 This is perhaps not surprising since transsynaptic degeneration or atrophy seems to be a non-specific consequence of retinal ganglion cell loss. It has been reported before in human glaucoma3 but also after enucleation in the macaque monkey.4,5 It is, however, of some interest to note that the pattern of loss in this case report, although not very pronounced, resembles that described in experiments …