This study looks at nerve damage and loss between the sexes. In this case they look after optic neuritis and find that men have more retinal nerve fibre layer thinning, indicative of nerve loss. This study suggests that males are more likely to suffer nerve loss than females and so points at a protective effect from sex hormones. I am sure MD2 will agree with this thought that males may be more susceptible to damage than females. Males tend to develop MS later than females but often develop progressive MS.