• 1. Koch SA, Rubin LF. Ocular sensitivity of dogs to topical tetracaine HCl. J Am Vet Med Assoc 1969; 154:1516.

  • 2. Kalf KL, Utter ME, Wotman KL. Evaluation of duration of corneal anesthesia induced with ophthalmic 0.5% proparacaine hydrochloride by use of a Cochet-Bonnet aesthesiometer in clinically normal horses. Am J Vet Res 2008; 69:16551658.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Monclin SJ, Farnir F, Grauwels M. Duration of corneal anaesthesia following multiple doses and two concentrations of tetracaine hydrochloride eyedrops on the normal equine cornea. Equine Vet J 2011; 43:6973.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Monclin SJ, Farnir F, Grauwels M. Determination of tear break-up time reference values and ocular tolerance of tetracaine hydrochloride eyedops in healthy horses. Equine Vet J 2011; 43:7477.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Amiel H, Koch PS. Tetracaine hydrochloride 0.5% versus lidocaine 2% jelly as a topical anesthetic agent in cataract surgery: comparative clinical trial. J Cataract Refract Surg 2007; 33:98100.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6. Chen X, Gallar J, Belmonte C. Reduction by antiinflammatory drugs of the response of corneal sensory nerve fibers to chemical irritation. Invest Ophthalmol Vis Sci 1997; 38:19441953.

    • Search Google Scholar
    • Export Citation
  • 7. Cochet P, Bonnet R. L'esthesie corneene (corneal esthesia). Clin Ophthalmol 1960; 4:127.

  • 8. Bartfield JM, Holmes TJ, Raccio-Robak N. A comparison of proparacaine and tetracaine eye anesthetics. Acad Emerg Med 1994; 1:364367.

    • Search Google Scholar
    • Export Citation
  • 9. Moreira LB, Kasetsuwan N, Sanchez D, et al. Toxicity of topical anesthetic agents to human keratocytes in vivo. J Cataract Refract Surg 1999; 25:975980.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Sun R, Hamilton RC, Gimbel HV. Comparison of 4 topical anesthetic agents for effect and corneal toxicity in rabbits. J Cataract Refract Surg 1999; 25:12321236.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Grant RL, Acosta D. Comparative toxicity of tetracaine, proparacaine and cocaine evaluated with primary cultures of rabbit corneal epithelial cells. Exp Eye Res 1994; 58:469478.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12. McGee HT, Fraunfelder FW. Toxicities of topical ophthalmic anesthetics. Expert Opin Drug Saf 2007; 6:637640.

  • 13. Liu Q, McDermott AM, Miller WL. Elevated nerve growth factor in dry eye associated with established contact lens wear. Eye Contact Lens 2009; 35:232237.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14. Millodot M. A review of research on the sensitivity of the cornea. Ophthalmic Physiol Opt 1984; 4:305318.

  • 15. Stiles J, Krohne S, Rankin A, et al. The efficacy of 0.5% proparacaine stored at room temperature. Vet Ophthalmol 2001; 4:205207.

  • 16. Barrett P, Scagliotti R, Meredith R, et al. Absolute corneal sensitivity and corneal trigeminal nerve anatomy in normal dogs. Prog Vet Comp Ophthalmol 1991; 1:245254.

    • Search Google Scholar
    • Export Citation
  • 17. Chan-Ling T. Sensitivity and neural organization of the cat cornea. Invest Ophthalmol Vis Sci 1989; 30:10751082.

  • 18. Kaps S, Richter M, Spiess BM. Corneal esthesiometry in the healthy horse. Vet Ophthalmol 2003; 6:151155.

  • 19. Brooks DE, Clark CK, Lester GD. Cochet-Bonnet aesthesiometer-determined corneal sensitivity in neonatal foals and adult horses. Vet Ophthalmol 2000; 3:133137.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20. Binder DR, Herring IP. Duration of corneal anesthesia following topical administration of 0.5% proparacaine hydrochloride solution in clinically normal cats. Am J Vet Res 2006; 67:17801782.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21. Herring IP, Bobofchak MA, Landry MP, et al. Duration of effect and effect of multiple doses of topical ophthalmic 0.5% proparacaine hydrochloride in clinically normal dogs. Am J Vet Res 2005; 66:7780.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Weiss JS, Goren MB. The effect of corneal hypesthesia on the duration of proparacaine anesthetic eyedrops. Am J Ophthalmol 1991; 112:326330.

    • Crossref
    • Search Google Scholar
    • Export Citation

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Effects of action of proparacaine and tetracaine topical ophthalmic formulations on corneal sensitivity in horses

Karen L. Sharrow-ReabeDepartment of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48823.

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Wendy M. TownsendDepartment of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48823.

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Abstract

Objective—To compare the corneal anesthetic effects and duration of action of 2 ophthalmic anesthetic agents in horses.

Design—Prospective, randomized masked crossover study.

Animals—8 clinically normal adult horses.

Procedures—Corneal sensitivity was determined by measuring each eye's corneal touch threshold (CTT) with a Cochet-Bonnet esthesiometer. Each eye's baseline CTT was recorded prior to anesthetic instillation at 0 minutes and every 10 minutes thereafter for 60 minutes. Each eye was randomly assigned to receive 2 of 4 treatments: 0.5% aqueous proparacaine ophthalmic solution (aqueous proparacaine; 8 eyes); 0.5% aqueous tetracaine ophthalmic solution (aqueous tetracaine; 8 eyes); 0.5% viscous tetracaine ophthalmic solution (viscous tetracaine; 8 eyes); and saline (0.9% NaCl) eyewash solution (8 eyes) as a negative control. There was a 48-hour washout period. Every horse received all treatments.

Results—Median baseline CTT of eyes was 4.5 cm (range, 0.5 to 6 cm). Median CTT for saline solution–treated eyes never differed significantly from baseline. The maximum anesthetic effect with the other 3 treatments occurred at 10 minutes. Median CTT of eyes at 10 minutes was 0.5 cm (range, 0 to 2.5 cm) with aqueous proparacaine treatment, 0.25 cm (range, 0 to 2.0 cm) with aqueous tetracaine treatment, and 0 cm (range, 0 to 0.5 cm) with viscous tetracaine treatment. Maximum anesthetic duration was 20 minutes with aqueous proparacaine and aqueous tetracaine treatments and 30 minutes with viscous tetracaine treatments.

Conclusions and Clinical Relevance—Treatment of eyes with viscous tetracaine resulted in the greatest decrease in CTT and the longest duration of action, compared with treatment with aqueous proparacaine or aqueous tetracaine.

Abstract

Objective—To compare the corneal anesthetic effects and duration of action of 2 ophthalmic anesthetic agents in horses.

Design—Prospective, randomized masked crossover study.

Animals—8 clinically normal adult horses.

Procedures—Corneal sensitivity was determined by measuring each eye's corneal touch threshold (CTT) with a Cochet-Bonnet esthesiometer. Each eye's baseline CTT was recorded prior to anesthetic instillation at 0 minutes and every 10 minutes thereafter for 60 minutes. Each eye was randomly assigned to receive 2 of 4 treatments: 0.5% aqueous proparacaine ophthalmic solution (aqueous proparacaine; 8 eyes); 0.5% aqueous tetracaine ophthalmic solution (aqueous tetracaine; 8 eyes); 0.5% viscous tetracaine ophthalmic solution (viscous tetracaine; 8 eyes); and saline (0.9% NaCl) eyewash solution (8 eyes) as a negative control. There was a 48-hour washout period. Every horse received all treatments.

Results—Median baseline CTT of eyes was 4.5 cm (range, 0.5 to 6 cm). Median CTT for saline solution–treated eyes never differed significantly from baseline. The maximum anesthetic effect with the other 3 treatments occurred at 10 minutes. Median CTT of eyes at 10 minutes was 0.5 cm (range, 0 to 2.5 cm) with aqueous proparacaine treatment, 0.25 cm (range, 0 to 2.0 cm) with aqueous tetracaine treatment, and 0 cm (range, 0 to 0.5 cm) with viscous tetracaine treatment. Maximum anesthetic duration was 20 minutes with aqueous proparacaine and aqueous tetracaine treatments and 30 minutes with viscous tetracaine treatments.

Conclusions and Clinical Relevance—Treatment of eyes with viscous tetracaine resulted in the greatest decrease in CTT and the longest duration of action, compared with treatment with aqueous proparacaine or aqueous tetracaine.

Contributor Notes

Dr. Sharrow-Reabe's present address is Bay Area Pet Hospital, 844 Front St, Traverse City, MI 49686.

Dr. Townsend's present address is Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906.

Presented in part at the 40th Annual Conference of the American College of Veterinary Ophthalmologists, Chicago, November 2009.

Address correspondence to Dr. Townsend (Townsenw@purdue.edu).