A review of ophthalmic local and regional anesthesia in dogs and cats.

OBJECTIVE: Orbital and globe surgeries are commonly performed in companion animals and are considered to cause moderate to severe pain. Regional anesthesia techniques can provide complete sensory blockade, analgesia for painful procedures and improve surgical conditions. The purpose of this review is to summarize local and regional anesthesia techniques for ophthalmic surgery in dogs and cats with emphasis on veterinary publications in the past 12 years.

DATABASES USED: Review of the literature was conducted using PubMed and Google Scholar. The search terms were 'ophthalmic regional anesthesia', 'retrobulbar anesthesia', 'peribulbar anesthesia', 'sub-Tenon's anesthesia', 'intracameral anesthesia', 'eye infiltration', 'dogs' and 'cats'. Further studies and reports were obtained from the reference lists of the retrieved papers. In addition, related veterinary anatomy, ophthalmology and regional anesthesia books were reviewed.

CONCLUSIONS: Reported techniques include regional techniques such as retrobulbar anesthesia, peribulbar anesthesia and sub-Tenon's anesthesia, and local techniques such as eyelid and conjunctival infiltration, intracameral anesthesia, splash block and insertion of intraorbital absorbable gelatin sponge infused with local anesthetic. Administration guidelines, indications and contraindications, and complications of each technique are discussed. Regional anesthesia techniques were reported to be effective during ophthalmic surgeries and are recommended for use as part of the anesthetic regimen and pain management in animals. However, the veterinary literature is still lacking controlled clinical trials and adverse events reports; therefore, there is very little evidence for choosing one technique over another.