My suggestion is to add different kinds of pupils,
Different pupils could give you different improvements.
Like a snake pupil could be earned earned by killing ten rogue males or wanderers and give away a distasteful look or even a new buff being intimidation
Crescent eyes could be earned by earned by not using any energy on a nicheling for ten days ( five days, five nights ) and give a nocturnal vision, adding a night in the day cycle and would give the nocturnal effect, though if any sleeping nichelings were attacked by a bearyena they would wake up with one energy, but saying this you could have Nighttime nichelings though they'd only have one energy, as not to debuff the crescent eyes.
Believe it or not some animals have W shaped pupils so don't @ me xd
W Pupils could increase sight in water, since some water dwelling frogs have these eyes, with this also comes a suggestion poorer eye-sight in water, earned by having a entire three generations living underwater
Geckos have pupils that are explained like this 'thin string of pearls' -w-
'thin string of pearls' pupils could give a better view behind the nicheling, adding the aspect of bearyena ambush/ surprise attack, earned by having a 0 attack nicheling ambushed by a bearyena
Feline pupils could give a extra tile of sight e.g. 4 tiles of sight, being earned by having at least two generations of good eyesight ( In a row )
If anyone has got more pupils with buffs and ways of being earned comment them :3