Ok so I'm surprised no one has suggested this yet, at least not that I could find! I checked a few pages and searched the term lens luxation and giant eyes and couldn't find anything, if someone has suggested this I'm incredibally sorry, just let me know! So some people may have heard of Matilda the alien cat, her eyes were incredibally enlarged due to a condition called lens luxation. I did a bit of searching and found that lens luxation can be caused by a mutation I believe! I figure the mutation would probably work very similarly to blind but if anyone has any other suggestions or idea please tell me! I believe the condition is more common in dogs but clearly it can happen in cats such as in the case of Matilda (who had her eyes removed eventually, As the mutation does cause pain and other problems) I couldn't find any cases of it actually happening in lions but I believe there are a few mutations on here that don't have any actual lion cases! Also I might do a sketch of how it could look at some point but I suck at drawing lions so idk lol Here is an example of what it looks like, this is a picture of Matilda I found online: Pic
EDIT: It was brought to my attention that actually what causes the eye enlargement part is glaucoma which can be caused from certain forms of lens luxation, I think this all can still work as a mutation though as that just means the form the lions would have causes the glaucoma aspect?