Ophthalmic Exam 4

When starting the ophthalmic exam holding the ophthalmoscope several inches from the eye, place the diopter setting on °3 or °4 (red 3 or 4) so as to focus on the retina. The focus can be refined by rotating the wheel that controls the diopter lenses. One can change the diopter settings to a more positive reading and progressively focus on areas between the retina and the cornea.

It is usually necessary to dilate the eye for a full exam, although a cursory view of the retina can be obtained and it is usually possible to see the horse's optic nerve clearly, even without mydriasis. Usually when the eye is first examined at this angle, one will have a view of the tapetal region. In order to view the optic nerve, it is necessary to look ventrally just below the tapetal/nontapetal junction. The disk can be found in this region. Then, look at different angles so as to evaluate the entire retina. Then move through to the positive diopter setting to examine the vitreous, lens and anterior segment of the eye. Remember that the direct ophthalmoscope head does magnify. Note that one should stabilize one's hand holding the ophthalmoscope so as to avoid hitting the horse's face if he or she suddenly moves its head.

Continue with the ophthalmic exam. . . . .