A weepy, grossly swollen eye is a sure sign that something is amiss, but ocular problems in horses are not always so obvious. In fact, some of the more serious eye conditions, such as uveitis0, may produce only subtle signs that are easy to miss. Any of the following are cause for further investigation:
• Aversion to light. Bright light can be painful for a horse with an inflammatory eye condition such as uveitis. A horse who prefers to stay in the shadows, especially at times of year when he wouldn’t be seeking cooling shade, may be doing so protect a painful eye.
• Eyelashes that point downward. Equine lashes are typically oriented parallel to the ground or turned slightly upward. If you notice the lashes on one or both of your horse’s eyes point downward, it may be an indication of subtle swelling.
• Yellowing of the iris. Inflammation of the eye can cause the iris---the colored portion of the eye surrounding the pupil---to take on a yellowish tinge. Blue eyes suddenly appear green and brown eyes take on an unusual tan color. Both changes are reason to call your veterinarian for an ocular check.
• Lack of clarity in the pupil. The center of the horse’s eye is normally pitch-black and clear. A milky appearance can indicate that a cataract is forming as a result of on-going inflammation.
• A cloudy look to the entire globe. Fungal infections and inflammatory disease can cause a horse’s eye to take on a hazy, bluish appearance. If one eye looks less clear than the other, or if both look more clouded than you recall, it’s cause for investigation.
This article first appeared in EQUUS issue #469, October 2016.