The easy answers are;
"Inappropriate eye for body type", such as Insect eyes, stalk eyes, or a general creature's sight. Make a table, and sort it out; the bottom rung being ineffectual and weird eyes, high rung being useful eyes.
suggestions that I mgiht put down are;
Mole's eyes; Anything's better right? It's like trying to see out of pin holes. Darkvision 5 ft
Snake's Eyes/Infravision; (Mid-low) See's gradiants of heat rather than color. Can't be blinded by light, but by heat or cool. Never mistakes a vampire or illusion.
Bug's eyes; (Low Mid Range) Disorienting 50x vision; but it's better than nothing. Cannot really be disguised; cannot close eyes. Great passive perception
Fish eyes; (Mid range), perfectly usable, perfectly creepy. Can never close eyes, but cannot get dust in them.
Goat's/Cow's/Horse's eyes; (Low mid) Great passive perception, horrid depth perception.
Normal Eyes (Likely perfect middle)
Crocodile's/lizard's eyes; like normal, but have a clear eyelid that allow for water and keeping dust out- but this could also hamper clear vision
Elf's/cat's eyes; ( high middle) Slightly better vision and keen vision
Dwarf's eyes/Orc's eyes; (High mid) Normal and darkvision
Dragon's Eyes/(Other neat creature's); Lizard+Cat's eyes, plus the ability to see magic.
Golem's eyes/scrying eyes; (High) Magical eyes that cannot be damaged by normal means; darkvision and low light, may be detachable/sighted, may see magic
God's eyes; (The best) As true scrying, all the goddamn time, can be filtered.