1st. Ample breadth between the orbits. This is of great importance in the horse, in which we seek for intelligence, courage and indomitable energy. This confirmation does not indicate the size of brain, as the cranium is situated higher up, but by placing the eyes well outward, it indicates a wider range of vision, and usually implies large, clear eyes, and since interdependent parts tend to correspond in development and quality, this commanding vision bespeaks a large, active brain, intelligence, docility and activity.
2d. Full, prominent eyes. This may be excessive, either through primary conformation or disease. Abnormal convexity of the cornea implies myopia. But within normal limits the prominent eye suggests good health, condition and vigor, with ample cushions of fat under the bulb and a sound, well-developed condition of the eyeball and its muscles.
3d. Both eyes equal in all respects. Any variation in size, shape, color, fullness, clearness or in any other respect is at best unsightly, and implies not only defect but often disease as well.
4th. The iris should be lustrous, uniform in color and even in surface. Whether dark brown as in the horse, or yellow as in the dog, it should be brilliant. Any part that lacks lustre, being lighter brown, or yellow and dull like a dead leaf, usually indicates previous disease and a tendency to further trouble. Albinos and those in which the pigment is congenitally absent in patches must be considered as exceptions, yet, even in them, the peculiarity cannot be held to add to the beauty.
5th. All the Media (Cornea, aqueous humor, lens and vitreous) must be perfectly clear and translucent. The slightest cloudiness or opacity in any of these is a serious blemish and usually indicates disease, past or present.
6th. The pupil should promptly and freely respond to light and darkness by contraction and expansion. Absence or tardiness of movement indicates impaired vision, from disease of the eye, its nerves, or their nerve centres.
7th. Each cornea should have a median convexity, uniform in all directions implying the absence of myopia, preshyopia and astigmatism. Any deviation from this will interfere with the perfection of sight, and endanger shying and other troubles.
8th. Under ordinary light the pupil should appear black throughout. In the larger animals such dilation of the pupil as to expose the tapetum lucidum under such circumstances implies impaired vision (amblyopia, amaurosis), inflammation of the iris or undue intraocular pressure. A white color or spot shows cataract.
9th. The lids must be open and mobile without excessive dilation. Tardily moving or semi-closed lids, distorted by scar or angle, everted or inverted, are unattractive and usually imply disease in the eye, nerves or brain.
10th. The unpigmented portion of the sclera should be light pink. The dark red of congestion and the pallor of anæmia are equally objectionable.