Ophthalmological Examination in our Laboratories

Abstract

The eye is one of the organ to be evaluated in toxicity studies. Eye examinations, however, have not been standarized and are totally dependent upon each institute in Japan. In this paper we describe how the eye is assessed in our laboratories for the effects of various test compounds administered in routine toxicity studies using rats and dogs, and we hope that this will stimulate discussion among workers in this field.

The anterior segment of the eye is examined using a slit lamp binocular microscope and an indirect ophthalmoscope without an aspheric lens. We feel it more practical to make the axis of the slit lamp free, so that the light beam may be directed to the subjects with less difficulity, even into the lens of rats, though their eyes are small for slit lamp examinations. In dogs, corneal opacity, lenticular abnormalities and their location may be detected in most cases, although roughly, with an indirect ophthalmoscope.

For the fundus, indirect ophthalmoscopy is employed. Care must be taken when albino rats are subjected to the eye examinations since the diagnosis of light-induced retinopathy may indicate the limits of its use. These examinations are conducted by two or more investigators discussing the findings at which they are looking. Final diagnosis is then made on the basis of results from ophthalmological examinations together with those from histopathological examinations.