Equis ISSN 2398-2977

Eyeball: tonometry

Contributor(s): Dennis E Brooks, Alison Clode, Graham Munroe, John Parker

Introduction

Uses

  • Assessment of intraocular pressure as part of examination of the eye.

Advantages

  • Digital tonometry is simple to carry out, requires no special instrumentation and soft/turgid globes are easily detected.

Must be used with pupil size. Dilated pupils are associated with glaucoma in many cases.

  • Electronic applanation tonometers are accurate, easy to use, portable, require no speical positioning of the eye and allow evaluation of the response to therapy.
  • Rebound tonometers have demonstrated reliability in normal equine eyes.

Disadvantages

  • Digital tonometry is subjective.
  • All methods can be affected by blepharospasm, extraocular muscle rigidity, eyelid swelling   Eyelid: trauma  or enophthalmos.
  • Electronic tonometers are expensive.
  • Rebound tonometers require the horse's eye be directed forward to allow positioning of the tonometer parallel to the ground.
  • The effect of corneal surface disease on the accuracy of rebound tonometry has not been determined.
  • The position of the horse's eyes precludes using the Schiotz tonometer.

Requirements

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Preparation

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Procedure

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Aftercare

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Knollinger A M, La Croix N C, Barrett P M & Miller P E (2005) Evaluation of a rebound tonometer for measuring intraocular pressure in dogs and horses. JAVMA 227 (2), 244-248 PubMed.
  • Smith P J, Gum G G, Whitley R D, Samuelson D A, Brooks D E & Garcia-Sanchez G A (1990) Tonometric and tonographic studies in the normal pony eye. Equine Vet J Suppl 10, 36-38 PubMed.


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