Why refraction is important to a crocodile?

Crocodiles are amphibious reptiles which hunt prey both on land and in water. Previous refractive studies have suggested that their eyes can focus objects in air and that their ability to refocus the eye underwater may be limited. Examination of the plane of focus of six species of crocodiles both in air and underwater has revealed that they are generally well focused in air for distant targets and severely defocused underwater. These results suggest that sensory systems other than vision must play an important role in prey capture underwater.