Answer: Myth AND Real – depends on how you look at it…..
Cataracts in horses are not an uncommon problem and can occur as the result of trauma, inflammation (such as that seen with chronic uveitis), and undetermined causes or as a congenital condition as observed with foals. In a recent retrospective study of the “visual outcome” (the degree to which the horse was able to see) of cataract surgery, the medical records of 95 foals and horses that had phacoemulsification surgery (the process by which the lens of the eye is emulsified with an ultrasonic tool with the resulting liquid being aspirated from the eye and replaced with saline to maintain the integrity of the front chamber of the eye) were reviewed for this project. Of these 95 horses, 16 required surgery in both eyes, for a total of 111 cataracts that were removed. Of those, 102 eyes were blind before surgery, with 97 eyes regaining sight almost immediately after surgery. Almost half of these surgeries were performed in foals.
Visual outcomes: 83 horses had visions for less than one month postop, 47 had vision for up to 6 months postop, 33 had vision for up to 12 months postop, and 25 had vision for more than 25 months. “Success equals vision,” the researcher’s wrote, and it was determined that 26.3% of the horses could still see and continue their normal, natural activity > 2 years after their surgery. “We are at the beginning of cataract surgery in horses,” said Dr. Brooks. “Some horses do very well, but a majority continue to have vision problems after surgery.”
So, is a 26.3% chance of sight “reasonable”? Perhaps in the face of blindness, especially if both eyes are affected, the answer may very well be “Yes!” Make no mistake, these horses have to be managed very carefully after surgery and this can be a “high maintenance” and expensive endeavor for even the most dedicated horse owner. But, to be able to return vision to an otherwise blind horse could quite possibly make all of the investment, both in time and dollars seem very worthwhile.
Scientific Article: Brooks, DE, Plummer, CE et al.(2104) “Visual outcomes of phacoemulsification cataract surgery in horses: 1990-2013.” Veterinary Ophthalmology.
doi:10.111/vop.12168, published online: 28 APR 2014.
Companion Article: Rosenthal, M. “The Gift of Sight”, The Modern Equine Vet. Vol. 4, issue 5 2014, pp 4-5.