Ophthalmometry without patient fixation

Because of the asphericity of the cornea, proper ophthalmometry requires the visual axis of the eye, the optical axis of the ophthalmometer, and the corneal apex to be coincident. The animal subject and the human patient cannot always direct their visual axis to the axis of the instrument. This paper describes the attachment of a photographer's tripod pan arm to the Haag Streit ophthalmometer and the method devised, which allows accurate corneal curvature measurement in cases of nonfixating subjects.