Biometric study of the canine eye, using A-mode ultrasonography.

A biometric study, using A-mode ultrasonography, was done on 32 eyes in 17 clinically normal dogs in vivo. A ringstand technique, using a saline bath supported by a plastic membrane, was used for applying ultrasound to the eye. Four intraocular dimensions were measured, including the distance from the anterior cornea to the anterior lens surface, the lens thickness, the distance from the posterior lens surface to the retina, and the distance from the anterior cornea to the retina. Statistical difference was not found between the total axial length of the right eye compared with the length of the left eye. There was, however, a significant increase of the total axial length of the eye in the male over that in the eye in the female dog (P less than 0.05). Tissue velocities for ultrasound in the canine aqueous and vitreous were equated to the velocity of ultrasound in distilled water at 38.6 C. The tissue velocity of the canine lens was determined experimentally to be 1,710 m/s and was shown to be greater than was the lens velocities in other species. Seemingly, adverse effects from ultrasound exposure were not seen.