Equine Cataracts

Survival techniques differ among animals, but many have highly developed senses of sight, smell, or hearing to detect danger and escape. Horses do not have antlers or horns to protect themselves from danger. They, instead, have exceptional sight and are able to spot the movement of potential predators. Most horses today do not need this safeguard often, but they are expected to perform in ways that require their visual system to perform optimally. A healthy visual system is a vital part of a horse’s health. A horse’s visual system can be affected by an array of conditions, but cataracts are an important condition that can affect horses of all ages, particularly the aging horse.

What is a cataract?

A cataract is an opacity within the lens tissue. The lens is a flattened, transparent disc located behind the iris, in the pupil. It helps focus images onto the retina. In order to have vision, light must reach the retina at the back of the eye. If the lens becomes opaque, light will not be able to reach the retina, and vision will be impaired.

What causes cataracts?

Cataracts are generally caused by molecular changes in the lens fibers and proteins which result in a loss of transparency, but there are several different causes of cataracts. Some include equine recurrent uveitis (ERU), ocular injury or disease, age, and congenital.

Indications of Cataracts

Cataracts begin as an opacity in a small area of the lens and can progress to an opacity of the entire lens. The first indication of cataract formation is usually visual impairment. The horse may not be able to navigate its stall without bumping into things or may refuse to navigate unknown surroundings. Other indications include a bluish-white opacity in the pupil, squinting, redness of the eye, and ocular discharge.

Treatment

Cataracts can only be removed surgically to restore vision. To determine if your horse is a viable candidate for cataract removal surgery, his/her eyes should be evaluated by a veterinary ophthalmologist. Cataracts are removed by phacoemulsification, the same process used in human cataract surgery. The cost of cataract removal surgery ranges from $5000 to $7500, barring any complications.

Post-Operative Care

Your horse’s post-operative care will be labor-intensive initially, as he/she will require frequent medication for several weeks after surgery. Your horse’s exercise should be restricted to a minimum for two to four weeks after surgery. The horse should be kept in a darkened stall during this time in order to adjust to his/her new vision. Post-operative evaluation appointments will be required to monitor your horse’s progress.

For more information on this topic, contact your veterinarian or visit these sites: The Equine Eye and Equine Cataracts.     

By Amber Long, Bladen County Summer Intern