Researchers in Toronto have discovered that glaucoma affects your patients' ability to see color and motion because of a loss of specific nerve cells in the brain. Study author Yeni H. Y�cel, M.D., says, "We counted the number of neurons in the lateral geniculate nucleus, which conveys visual information from the eye to the visual cortex."

Dr. Y�cel and fellow researchers studied four monkeys with experimentally induced glaucoma in the right eye -- the glaucoma group -- and five control group monkeys. The study found that the mean number of neurons in the first magnocellular layer were significantly decreased in the glaucoma group compared with the control group. Also, the mean number of neurons in the fourth and sixth parvocellular layers decreased significantly in the glaucoma group compared with the control group.

The researchers concluded that significant loss of lateral geniculate nucleus relay neurons, terminating in the primary visual cortex, occurred in the magnocellular and parvocellular layers in the glaucoma group.

In addition, the study stated that knowledge of the fate of neurons in the central visual system might lead to a better understanding of the nature and progression of visual loss in glaucomatous optic neuropathy.