• 1. Griepentroy GJ, Lucarelli MJ. Functions of the orbit and adnexa. In: Levin LA, Nilsson SFE, ver Hoeve J, et al, eds. Adler's physiology of the eye. 11th ed. Edinburgh: Saunders/Elsevier, 2011;333349.

    • Search Google Scholar
    • Export Citation
  • 2. Tsubota K, Hata S, Okusawa Y, et al. Quantitative videographic analysis of blinking in normal subjects and patients with dry eye. Arch Ophthalmol 1996;114:715720.

    • Search Google Scholar
    • Export Citation
  • 3. Malbouisson JM, Messias A, Garcia DM, et al. Modeling upper eyelid kinematics during spontaneous and reflex blinks. J Neurosci Methods 2010;191:119125.

    • Search Google Scholar
    • Export Citation
  • 4. Cardona G, Garcia C, Seres C, et al. Blink rate, blink amplitude, and tear film integrity during dynamic visual display terminal tasks. Curr Eye Res 2011;36:190197.

    • Search Google Scholar
    • Export Citation
  • 5. Berke A, Mueller S. The kinetics of lid motion and its effects on the tear film. Adv Exp Med Biol 1998;438:417424.

  • 6. Garcia DM, Messias A, Costa LO, et al. Spontaneous blinking in patients with Graves’ upper eyelid retraction. Curr Eye Res 2010;35:459465.

    • Search Google Scholar
    • Export Citation
  • 7. Cher I. Blink-related microtrauma: when the ocular surface harms itself. Clin Experiment Ophthalmol 2003;31:183190.

  • 8. Wan T, Jin X, Lin L, et al. Incomplete blinking may attribute to the development of meibomian gland dysfunction. Curr Eye Res 2016;41:179185.

    • Search Google Scholar
    • Export Citation
  • 9. Hirota M, Uozato H, Kawamorita T, et al. Effect of incomplete blinking on tear film stability. Optom Vis Sci 2013;90:650657.

  • 10. Ousler GW, Abelson MB, Johnston PR, et al. Blink patterns and lid-contact times in dry-eye and normal subjects. Clin Ophthalmol 2014;8:869874.

    • Search Google Scholar
    • Export Citation
  • 11. Best LJ, Hendrix DVH, Ward DA. Tear film osmolality and electrolyte composition in healthy horses. Am J Vet Res 2015;76:10661069.

  • 12. Korb DR, Baron DF, Herman JP, et al. Tear film lipid layer thickness as a function of blinking. Cornea 1994;13:354359.

  • 13. Fenga C, Aragona P, Cacciola A, et al. Meibomian gland dysfunction and ocular discomfort in video display terminal workers. Eye (Lond) 2008;22:9195.

    • Search Google Scholar
    • Export Citation
  • 14. Wada S, Hobo S, Niwa H. Ulcerative keratitis in Thoroughbred racehorses in Japan from 1997 to 2008. Vet Ophthalmol 2010;13:99105.

  • 15. Collins M, Seeto R, Campbell L, et al. Blinking and corneal sensitivity. Acta Ophthalmol (Copenh) 1989;67:525531.

  • 16. Doughty MJ. Consideration of three types of spontaneous eyeblink activity in normal humans: during reading and video display terminal use, in primary gaze, and while in conversation. Optom Vis Sci 2001;78:712725.

    • Search Google Scholar
    • Export Citation
  • 17. Barbato G, Ficca G, Muscettola G, et al. Diurnal variation in spontaneous eye-blink rate. Psychiatry Res 2000;93:145151.

  • 18. Bacher LF, Smotherman WP. Spontaneous eye blinking in human infants: a review. Dev Psychobiol 2004;44:95102.

  • 19. Trost K, Skalicky M, Nell B. Schirmer tear test, phenol red thread tear test, eye blink frequency and corneal sensitivity in the guinea pig. Vet Ophthalmol 2007;10:143146.

    • Search Google Scholar
    • Export Citation
  • 20. Toshida H, Nguyen DH, Beuerman RW, et al. Evaluation of novel dry eye model: preganglionic parasympathetic denervation in rabbit. Invest Ophthalmol Vis Sci 2007;48:44684475.

    • Search Google Scholar
    • Export Citation
  • 21. Kirsty R, Andrew H, Meriel MC, et al. Cognitive differences in horses performing locomotor versus oral stereotypic behaviour. Appl Anim Behav Sci 2015;168:3744.

    • Search Google Scholar
    • Export Citation
  • 22. Koushan K, Skibell BC, Harvey JT, et al. Digital photography as a novel technique of measuring ocular surface dimensions. Orbit 2008;27:259265.

    • Search Google Scholar
    • Export Citation
  • 23. Doane MG. Interaction of eyelids and tears in corneal wetting and the dynamics of the normal human eyeblink. Am J Ophthalmol 1980;89:507516.

    • Search Google Scholar
    • Export Citation
  • 24. Somia NN, Rash GS, Epstein EE, et al. A computer analysis of reflex eyelid motion in normal subjects and in facial neuropathy. Clin Biomech (Bristol, Avon) 2000;15:766771.

    • Search Google Scholar
    • Export Citation
  • 25. Sforza C, Rango M, Galante D, et al. Spontaneous blinking in healthy persons: an optoelectronic study of eyelid motion. Ophthalmic Physiol Opt 2008;28:345353.

    • Search Google Scholar
    • Export Citation
  • 26. Wu Z, Begley CG, Situ P, et al. The effects of mild ocular surface stimulation and concentration on spontaneous blink parameters. Curr Eye Res 2014;39:920.

    • Search Google Scholar
    • Export Citation
  • 27. Bologna M, Marsili L, Khan N, et al. Blinking in patients with clinically probable multiple system atrophy. Mov Disord 2014;29:415420.

    • Search Google Scholar
    • Export Citation
  • 28. Chen T, Ward DA. Tear volume, turnover rate, and flow rate in ophthalmologically normal horses. Am J Vet Res 2010;71:671676.

  • 29. Frigerio A, Cavallari P. A closed-loop stimulation system supplemented with motoneurone dynamic sensitivity replicates natural eye blinks. Otolaryngol Head Neck Surg 2012;146:230233.

    • Search Google Scholar
    • Export Citation
  • 30. Schotanus MP, Koetje LR, van Dyken RE, et al. Stratified corneal limbal epithelial cells are protected from UVB-induced apoptosis by elevated extracellular K+. Exp Eye Res 2011;93:735740.

    • Search Google Scholar
    • Export Citation
  • 31. Miller C, Utter ML, Beech J. Evaluation of the effects of age and pituitary pars intermedia dysfunction on corneal sensitivity in horses. Am J Vet Res 2013;74:10301035.

    • Search Google Scholar
    • Export Citation
  • 32. Evinger C, Manning KA, Sibony PA. Eyelid movements. Mechanisms and normal data. Invest Ophthalmol Vis Sci 1991;32:387400.

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Blink patterns and kinematics of eyelid motion in ophthalmologically normal horses

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  • 1 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.
  • | 2 Department of Mathematics, College of Arts and Sciences, University of Tennessee, Knoxville, TN 37996.
  • | 3 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.
  • | 4 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.
  • | 5 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.

Abstract

OBJECTIVE To describe qualitative blinking patterns and determine quantitative kinematic variables of eyelid motion in ophthalmologically normal horses.

ANIMALS 10 adult mares.

PROCEDURES High-resolution videography was used to film blinking behavior. Videotapes were analyzed for mean blink rate, number of complete versus incomplete blinks, number of unilateral versus bilateral blinks, and subjective descriptions of blinking patterns. One complete blink for each horse was analyzed with image-analysis software to determine the area of corneal coverage as a function of time during the blink and to calculate eyelid velocity and acceleration during the blink.

RESULTS Mean ± SD blink rate was 18.9 ± 5.5 blinks/min. Blinks were categorized as minimal incomplete (29.7 ± 15.6%), moderate incomplete (33.5 ± 5.9%), complete (30.8 ± 13.1%), and complete squeeze (6.0 ± 2.8%); 22.6 ± 9.0% of the blinks were unilateral, and 77.3 ± 9.1% were bilateral. Mean area of exposed cornea at blink initiation was 5.89 ± 1.02 cm2. Mean blink duration was 0.478 seconds. Eyelid closure was approximately twice as rapid as eyelid opening (0.162 and 0.316 seconds, respectively). Deduced maximum velocity of eyelid closure and opening was −16.5 and 7.40 cm/s, respectively. Deduced maximum acceleration of eyelid closure and opening was −406.0 and −49.7 cm/s2, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE Kinematic variables of ophthalmologically normal horses were similar to values reported for humans. Horses had a greater percentage of complete squeeze blinks, which could increase tear film stability. Blinking kinematics can be assessed as potential causes of idiopathic keratopathies in horses.

Abstract

OBJECTIVE To describe qualitative blinking patterns and determine quantitative kinematic variables of eyelid motion in ophthalmologically normal horses.

ANIMALS 10 adult mares.

PROCEDURES High-resolution videography was used to film blinking behavior. Videotapes were analyzed for mean blink rate, number of complete versus incomplete blinks, number of unilateral versus bilateral blinks, and subjective descriptions of blinking patterns. One complete blink for each horse was analyzed with image-analysis software to determine the area of corneal coverage as a function of time during the blink and to calculate eyelid velocity and acceleration during the blink.

RESULTS Mean ± SD blink rate was 18.9 ± 5.5 blinks/min. Blinks were categorized as minimal incomplete (29.7 ± 15.6%), moderate incomplete (33.5 ± 5.9%), complete (30.8 ± 13.1%), and complete squeeze (6.0 ± 2.8%); 22.6 ± 9.0% of the blinks were unilateral, and 77.3 ± 9.1% were bilateral. Mean area of exposed cornea at blink initiation was 5.89 ± 1.02 cm2. Mean blink duration was 0.478 seconds. Eyelid closure was approximately twice as rapid as eyelid opening (0.162 and 0.316 seconds, respectively). Deduced maximum velocity of eyelid closure and opening was −16.5 and 7.40 cm/s, respectively. Deduced maximum acceleration of eyelid closure and opening was −406.0 and −49.7 cm/s2, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE Kinematic variables of ophthalmologically normal horses were similar to values reported for humans. Horses had a greater percentage of complete squeeze blinks, which could increase tear film stability. Blinking kinematics can be assessed as potential causes of idiopathic keratopathies in horses.

Supplementary Materials

    • Video S1 (PDF 38,783 kb)

Contributor Notes

Dr. Best's present address is Eye Specialists for Animals, 3515 American Dr, Colorado Springs, CO 80917.

Address correspondence to Dr. Ward (dward@utk.edu).