Current developments in equine cataract surgery

The purpose of this review is to discuss the evolution of equine cataract surgery over the past 50 years to its current stage. Equine cataract surgery is performed similarly compared with the techniques used in human ophthalmology and in other veterinary species. However, enough differences exist to make surgical lens removal and intraocular lens implantation in the horse an intrinsically unique endeavour. Due to the size of the adult equine globe, the introduction of species-specific instrumentation has provided the cornerstone to many of the changes made regarding surgical technique over the last 15-20 years. The continuing development of an equine specific, foldable intraocular lens implant (IOL) has provided much needed data supporting the use of such lenses in the horse to improve upon the post operative visual outcome. Finally, the methods utilised to assess visual capacity and the effects of intraocular lens implantation on the globe (e.g. ocular ultrasonography, electroretinography and streak retinoscopy) are gradually becoming more important in preoperative patient assessment and IOL development in the horse. It is the hope of the authors that a broader group of equine veterinarians will become aware of the many changes that have taken place in equine cataract surgery over the last half-century. Although aspiration was implemented nearly 40 years ago in foals for the treatment of congenital cataracts, phacofragmentation (phacoemulsification) techniques have only recently become routine in mature horses undergoing lens extraction.