Feline post-sterilization hyphema

Vet Ophthalmol. 2020 May;23(3):588-591. doi: 10.1111/vop.12760. Epub 2020 Mar 26.

Abstract

Objective: To determine incidence and risk factors of post-sterilization hyphema in shelter cats.

Animals studied: Retrospective medical record review of 1204 cats and prospective screening of 195 cats.

Procedures: The study consisted of three parts: (a) Survey responses were collected from 20 veterinarians, who perform high-quality high-volume spay-neuter (HQHVSN) in both shelter and public clinic settings; (b) medical records of 1204 cats were analyzed retrospectively over a 14-month time period; and (c) ophthalmic examinations, including tonometry, were performed prospectively on 195 cats before and after sterilization surgery over 8 weeks.

Results: Nine of 20 surveyed veterinarians reported having witnessed hyphema in cats following sterilization surgery. Retrospective review of 1204 medical record and prospective screening of 195 cats showed that three juvenile (<1 year of age) male cats (<2 kg) developed hyphema within 1 hour following surgery (0.2% incidence). In all three affected cats, anesthesia was induced with tiletamine/zolazepam (3 of 523 cats induced with this drug combination; 0.6% incidence), and hyphema resolved within 20 hours. Mean intraocular pressures as measured by Icare® TonoVet were (mean ± standard deviation) 11.5 ± 3.8 mm Hg and 21.7 ± 4.6 mm Hg for juvenile (<1 year of age) and adult (>1 year of age) cats, respectively.

Conclusions: Survey responses and three observed cases confirm the existence of feline post-sterilization hyphema with an estimated incidence of 0.2%. The underlying mechanism for this occurrence remains unknown.

Keywords: cat; hyphema; shelter medicine; sterilization; tiletamine; zolazepam.

MeSH terms

  • Animals
  • Cats / surgery*
  • Female
  • Hyphema / epidemiology
  • Hyphema / etiology
  • Hyphema / veterinary*
  • Hysterectomy / adverse effects
  • Hysterectomy / veterinary*
  • Incidence
  • Male
  • Michigan / epidemiology
  • Orchiectomy / adverse effects
  • Orchiectomy / veterinary*
  • Ovariectomy / adverse effects
  • Ovariectomy / veterinary*
  • Postoperative Complications / epidemiology
  • Postoperative Complications / etiology
  • Postoperative Complications / veterinary
  • Prospective Studies
  • Records / veterinary
  • Retrospective Studies