Cataracts are the clouding of the lens inside the eye which affects the horse's vision. The severity of vision loss depends on the location and extent of the opacity.
Cataracts can occur in horses of all ages and can be developmental (including congenital forms) or acquired (secondary). 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). Not all cataracts will require treatment, however it is best to have regular check ups with your veterinarian to catch them if they progress.