Cataract Formation and Surgery in Dogs: Our Progress and Future

Abstract

Cataract surgery in dogs has become highly successful in restoring vision, and is the most frequent intraocular surgery performed in the dog by veterinary ophthalmologists. Significant advances in canine cataract surgery have paralleled those in man and gradually evolved from the intracapsular cataract extraction (1950s), the extracapsular cataract procedure (1970s), to currently the phacoemulsification techniques. Cataract surgery in dogs differs from that in man because the canine lens is larger and the postoperative anterior uveitis more intense. By many comparisons, cataract surgery in children is quite similar to that in the dog. Modifications of cataract surgery have changed the preoperative, intraoperative and postoperative aspects and start with the selection of the patient, preoperative treatment and control of the lens-induced anterior uveitis, and routine evaluation by flash electroretinography (for generalized retinal degeneration) and ultrasonography (for vitreal degenerations and retinal detachments). The intraoperative advancements have been most significant and included the operating microscope, smaller and well designed surgical instruments, one-handed phacoemulsification units, prevention of fibrin formation and maintenance of mydriasis with intraocular heparin and epinephrine respectively, and smaller absorbable sutures. Canine intraocular lenses (IOLs) have been developed to provide emmetropia for dogs postoperatively. Postoperative advancements have concentrated on the medical control and resolution of the lens-in-duced uveitis. Challenges such as preventing capsular fibrosis, and successfully resolving postoperative aphakic glaucoma and retinal detachments remain. The success of cataract surgery varies by the time evaluated postoperatively but realistically appears to be about 90% within the first six months and then a slight decline to perhaps 80% in dogs with three year follow-ups.