Q. I recently purchased a Paint horse with a bald face with two blue eyes and pink skin around his eyes. I know I need to be careful of sunburn since his skin is pink, but are there any other potential problems that I need to know about in advance so I can prevent them? Are horses with blue eyes more sensitive to light or more prone to eye disorders than other horses? —Erika Andrews, Virginia

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A. Horses with pink skin around their eyes or nonpigmented eyelids are at high risk for developing a skin cancer called squamous cell carcinoma. It is very important that horses with nonpigmented eyelid skin or third eyelids avoid long exposure to direct sunlight. I recommend turning these horses out to pasture only at night or wear an ultraviolet light-protective fly mask. It is much easier to prevent squamous cell carcinoma than to treat it once it develops.

Horses with blue eyes have this appearance because the eye structure surrounding the pupil—the iris—has less pigment (just like the eyelids). Horses with blue irises have normal vision and are not at increased risk for eye disease, and the vast majority of horses are not more sensitive to light. But as these horses age, they may develop a condition called iris atrophy, which can result in iris tissue loss, causing them to subsequently become more sensitive to light. However, iris atrophy severe enough to cause substantial light sensitivity is very uncommon. If this does occur, place a fly mask on the horse when he is in direct sunlight.

Prior to the purchase of any horse, I recommend having your veterinarian thoroughly examine the horse’s eyes to ensure no pre-existing abnormalities are present. This is the only way to ensure that your horse has adequate visual capability to perform his or her intended activities