Fluorophotometric determination of aqueous humor flow rates in red-tailed hawks (Buteo jamaicensis)

摘要

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 mu L/min (range, 1.67 to 6.21 mu L/min), 2.86 +/- 0.88 mu L/min (range, 2.04 to 4.30 mu L/min), and 2.90 +/- 0.90 mu L/min (range, 1.67 to 4.42 mu L/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. (Am J Vet Res 2012;73:551-555)