No, if having eyes was neutral, that is, neither an advantage or a disadvantage, and an eyeless mutation occurred and survived as a variant, you would expect to see salamanders both with eyes and without them. But what we see is all eyeless in that cave. So, there must be a cost associated with having eyes in that environment: relatively easily injured and infected and requires real estate and caloric fuel in the brain. Therefore, the eyeless mutant replaced the variant with eyes because of the advantages of being eyeless there. Greg Shenaut