"But obviously, mice are not people, so whether exercise can prevent or ameliorate macular degeneration in human eyes is “impossible to know, based on the data we have now,”"

I have a fairly complex view of animal testing where I think it may be justified in some situations, but this type of testing in situations where you self-admit you didn't learn anything knowingly human-applicable when you could have done a more long term study just observing the eye health of multiple sets of older humans (one set which lives an active lifestyle and one which does not) is pretty fucked up.