Development of a contact lens for refracting aquatic animals

Development of a new technique for refracting the eye of unwieldy and large aquatic organisms in air is presented. The technique employs a contact lens to simulate underwater conditions. Refraction is performed through a flat front surface with an ophthalmoscope or a streak retinoscope. Data from 11 carcharhinid sharks (four species) indicate that the smaller eyes of inshore species are defocused relative to the eyes of offshore species.