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Fluorophotometric determination of aqueous humor flow rates in red-tailed hawks (Buteo jamaicensis)
American Journal of Veterinary Research (2012)
  • Michael Jones, University of Tennessee - Knoxville
  • Daniel A. Ward, University of Tennessee, Knoxville

OBJECTIVE: To determine aqueous humor flow rate (AHFR) in an avian species by use of anterior segment fluorophotometry. ANIMALS: 9 healthy red-tailed hawks (Buteo jamaicensis; 4 males and 5 females) that ranged from 8 months to 8 years of age. PROCEDURES: A protocol was developed for fluorophotometric determination of AHFR. Topical administration of 10% fluorescein was used to load the corneas, and corneal and aqueous humor fluorescein concentrations were measured approximately 5, 6.5, and 8 hours later. Concentration-versus-time plots were generated, and slopes and cornea-to-aqueous humor concentration ratios from these plots were used to manually calculate flow rates. RESULTS: Mean ± SD AHFRs for the right eye, left eye, and both eyes were 3.17 ± 1.36 μL/min (range, 1.67 to 6.21 μL/min), 2.86 ± 0.88 μL/min (range, 2.04 to 4.30 μL/min), and 2.90 ± 0.90 μL/min (range, 1.67 to 4.42 μL/min), respectively. The AHFRs were similar for right and left eyes. These flow rates represented a mean aqueous humor transfer coefficient of 0.0082/min, which is similar to that of mammalian species. CONCLUSIONS AND CLINICAL RELEVANCE: The AHFR in red-tailed hawks was similar to that of most mammalian species, and the fractional egress was almost identical to that of other species. This information will allow a greater understanding of aqueous humor flow in avian eyes, which is crucial when evaluating diseases that affect avian eyes as well as medications that alter aqueous humor flow.

Publication Date
Citation Information
Michael Jones and Daniel A. Ward. "Fluorophotometric determination of aqueous humor flow rates in red-tailed hawks (Buteo jamaicensis)" American Journal of Veterinary Research Vol. 73 Iss. 4 (2012)
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