Cataracts are the clouding of the lens inside the eye which affects the horse's vision, blocking images as opposed to light. Cataracts can be congenital, inherited, or acquired in horses. The severity depends on the location and extent of the lens opacity. If the entire lens is affected, it causes blindness. If the lens opacity only affects a smaller area, it may cause the horse to have blind spots in their field of vision.
Cataracts are classified according to the degree of opacity (incipient, immature, mature or hypermature), location (anterior, posterior, perinuclear, nuclear or equatorial, capsular, subcapsular or cortical), age of onset (congenital, juvenile, senile) or cause (traumatic, inflammatory, toxic or metabolic).
Treatment Options for Horses with Cataracts
Not all cataracts may require treatment. For those that do, cataracts can be surgically removed through a procedure known as phacoemulsification. It involves the surgeon using a special probe that vibrates at ultrasonic frequencies to liquefy and break apart the cataract followed by vacuuming it out of the eye. This procedure has had good short-term success for horses with cataracts, however it has not been as favorable for long-term success.