RETROSPECTIVE INVESTIGATION OF CATARACT MANAGEMENT IN AVIAN SPECIES IN A ZOOLOGIC COLLECTION.

A review of avian cataracts at the Wildlife Conservation Society's Bronx Zoo between 1992 and 2011 was conducted. Ninety cataracts in 54 birds from 42 species were identified. Cataracts were found primarily during examination for ocular abnormalities (29/54, 53.7%) or opportunistically (13/54, 24.1%) and were most commonly diagnosed as mature (22/90, 24.4%). Systemic medical conditions diagnosed in these birds included West Nile virus (4/54, 7.4%), head trauma (3/54, 5.6%), plumbism and Salmonella Pullorum (1/54, 1.9%), Marek's disease (1/54, 1.9%), leukocytosis (1/54, 1.9%), and hyperglycemia (1/54, 1.9%). Cataracts were progressive in seven birds of four species. Unilateral enucleation was performed in 2/54 (3.7%) birds, and 12/54 (22.2%) underwent cataract removal (phacoemulsification in 16 eyes and standard extracapsular cataract extraction in 2 eyes). Concurrent ocular abnormalities, such as corneal scarring and lens-induced uveitis, were seen in 2/18 (11.1%) eyes preoperatively in the group undergoing cataract removal, 2/2 (100%) eyes preoperatively in the group undergoing enucleation, and 33/70 (47.1%) of eyes that did not undergo surgery. For birds undergoing cataract removal, complications included successfully treated cardiorespiratory arrest intraoperatively (1/12, 8.3%) as well as postanesthetic complications of acute respiratory distress and tracheal stricture (2/12, 16.7%). The most common postoperative ocular abnormalities included posterior capsular opacity (4/18 eyes, 22.2%) and corneal scarring (2/18 eyes, 11.1%). Lens cortical regrowth and marked posterior lens capsular opacity occurred in one eye of one bird after phacoemulsification, necessitating a second ocular surgery. A successful outcome, as determined by improved postoperative visual acuity, was seen in 10/12 (83.3%) birds undergoing cataract removal, and 5/12 (41.7%) of these birds were alive >3 yr after surgery. The results of this review will aid clinicians in identifying common stages of cataracts, determining eligibility for cataract surgery, and managing postoperative complications in avian patients.