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Related Experiment Videos

The phenol red thread tear test in large Psittaciformes.

Elaine Holt1, Karen Rosenthal, Frances S Shofer

  • 1Department of Clinical Studies, School of Medicine, Matthew J Ryan, Veterinary Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA. eholt@rvc.ac.uk

Veterinary Ophthalmology
|February 25, 2006
PubMed
Summary

The phenol red thread (PRT) tear test is a practical method for measuring tear production in large Psittaciformes, but reproducibility was poor. Geographic location significantly influences PRT tear test results in pet birds.

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Area of Science:

  • Veterinary Ophthalmology
  • Avian Medicine

Background:

  • Tear production measurement is crucial for diagnosing ocular conditions in birds.
  • Standardized methods for assessing tear production in large Psittaciformes are lacking.

Purpose of the Study:

  • To establish a standard method for measuring tear production in large Psittaciformes using the phenol red thread (PRT) tear test.
  • To determine mean PRT tear test values in clinically normal pet birds.
  • To evaluate the reproducibility of the PRT tear test in this population.

Main Methods:

  • The PRT tear test was performed on two geographically distinct populations of healthy, large Psittaciformes.
  • The PRT was placed under the upper eyelid, and eyelids were held closed during the test.
  • Repeatability was assessed by re-testing after 2 months (pilot study) or 5 minutes (study population).

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Main Results:

  • Mean PRT tear test values varied between the pilot and study populations, with values ranging from 19.1 mm to 28.2 mm per 15 seconds.
  • Repeatability between tests was poor in the study population.
  • Geographic location appeared to significantly influence the results.

Conclusions:

  • The PRT tear test is a feasible method for assessing tear production in large Psittaciformes, though anatomical adaptations may be needed.
  • The study did not demonstrate good reproducibility of the PRT tear test in clinically normal birds.
  • Further research is needed to refine the PRT method and understand factors influencing tear production in avian species.