['To determine whether brain-derived neurotrophic factor (BDNF), a neuroprotectant in the small rat eye, might also serve as an effective neuroprotectant in larger vertebrate eyes. METHODS. A cat optic nerve crush model was combined with standard histologic staining and analysis techniques. Twenty-nine animals were studied, with the noninjected eye serving as the control eye.', 'No treatment, or intravitreal injection of sterile water, resulted in an approximately 50% loss of ganglion cells 1 week after nerve crush. By contrast, the mean percentages of surviving ganglion cells measured in eyes receiving injections of 15, 30, 60, and 90 microg BDNF at the time of the nerve damage were 52%, 81%, 77%, and 70%, respectively. Similar values were obtained for ganglion cell density. Cell size measurements suggest a complex response among the different classes of cat ganglion cells; 30 microg BDNF treatment retained the highest number of large ganglion cells, whereas 90 microg minimized the loss of medium-sized neurons and retained normal proportions of large, medium, and small ganglion cells.'] Does bDNF enhance retinal ganglion cell survival in cats with optic nerve damage?