The refractive error of the fish eye.
D000818:Animals; D001699:Biometry; D002829:Choroid / Q000473:pathology; D003116:Color; D003530:Cyprinidae; D005393:Fish Diseases / Q000175:diagnosis / Q000473:pathology*; D005399:Fishes; D005615:Freezing; D007908:Lens, Crystalline / Q000473:pathology; D009887:Ophthalmoscopy; D012030:Refractive Errors / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D012160:Retina / Q000473:pathology; D012487:Salmonidae; D014822:Vitreous Body / Q000473:pathology