While they aren't used to improve vision in horses, soft contact lenses can be used to protect the eye and facilitate healing in horses with non-infected ulcerations. Robert Lowe, BVSc, MRCVS, CertVOphthal, of Downland Veterinary Group in Hampshire, United Kingdom, discussed the use of contacts for horses at the 43rd annual British Equine Veterinary Association Congress held Sept. 15-18 in Birmingham.

"I use them often, on any case with superficial ulceration and no infection," Lowe said. "I think they're quite underused. They're used a lot in dogs and cats, but horses as well as humans are better species for them because the eyelids are tighter and hold the lens in better. There's less chance of them rubbing the lenses out."

Reasons to avoid contacts for a particular horse include reduced tear production, infection, deep corneal ulceration where there's a risk of rupture during lens placement, and abnormal corneal curvature (including raised corneal masses), he said.

Equine lenses come in two sizes–34 mm diameter with 18 base curvature (BC), and 32 mm/17 BC (for comparison's sake, human lenses are about 14 mm/8.60 BC). Lowe recommends using the larger size for horses and the smaller for ponies and foals. The lenses cost about �45 each (about $76 U.S.)