6th. The weeping eye. This is always a condition of disease. It may be due to irritant gases, or solid particles, to inturned cilia, everted lids, conjunctivitis or a variety of other conditions. A careful examination may show whether it is only a transient and remediable fault of a good eye or a permanent and irremediable defect.
7th. The blear eye. With swelling and scabbing of the edges of the lids and Meibomian glands, and congestion of the adjacent conjunctiva, there is usually some blurring of the surface of the transparent cornea. The trouble is mostly chronic and constitutes a serious objection.
8th. The watch eye. In this, as in the albino, there is a lack of pigment, so that the iris and sclerotic are white or bluish white in part or in whole. Such an eye may be good and durable, but not beautiful nor attractive.
9th. Blindness of one or both eyes. In all such cases the pupil remains fixed and immovable, showing no accommodation to light and darkness, and there is a lack of prompt responsiveness on the part of the eye to sounds and objects. In amaurosis, glaucoma and cataract especially, the pupil remains widely open, and alert movements of the ears are employed to make up for the lack of sight. The condition often comes from internal ophthalmia, such as the recurrent form, and is associated with atrophy of the bulb.
10th. Eyes of unequal size. This usually implies serious disease in one, not infrequently recurring ophthalmia.
11th. Too flat corneal surface. In this case there is a manifest lack of the normal projection, the anterior surface of the cornea describing the arc of a larger circle, the visual rays coming from a distance alone converge on the retina and presbyopia occurs. In this as in myopia and other visual imperfections a horse is liable to stumble and, if nervous, to shy.
12th. Ovoid Cornea. In such cases the front of the transparent cornea has an ovoid outline the arc formed by it in one direction being that of a greater circle, than the arc which crosses this at right angles. In consequence of this, the rays impinging on the outer portions of these respective arcs do not converge to the same point on the retina and a blurred and imperfect image results. This astigmatism causes the subject to stumble and, if nervous, to shy.
SYSTEMATIC INSPECTION OF THE EYE.
System in Examination. Eyelids: cilia: lachryneal puncta: mucosa, light pink, brick red, yellow, puffy, dropsical: Ciliary vessels deep, immovable; nictitans; transparent cornea equally smooth, glossy, with clear image at all points: foreign body on cornea: corneal ulcer: opacities in aqueous humor: iris and pupil: corpora nigra: changes in passing from darkness to light: pupillary membrane: adhesions of iris: intraocular pressure: contracted pupil: hole in iris. Oblique focal illumination of cornea, aqueous humor, iris, lens, Purkinje-Sanson images.
In examining animals for soundness and especially the horse or dog, the condition of the eye must be made one of the most important subjects of inquiry, as a disease or defect may render the animal altogether unsuited to the object to which it is destined. As in every other field of diagnosis thoroughness is largely dependent on the adoption of a system which will stand in the way of any flaw being too hastily overlooked. Many of the points to be noted will be decided at a glance, yet this does not obviate the necessity of turning over in the mind, in succession, the different points of inquiry, and directing the necessary attention, however hastily, to each in turn. The following points should be observed: