advertisement
OBJECTIVE: To determine aqueous humor flow rate in clinically normal dogs, using fluorophotometry. ANIMALS: Twenty clinically normal beagles. PROCEDURE: A study was performed on five dogs to establish an optimal protocol for fluorophotometric determination of aqueous humor flow rate. This protocol then was used to measure aqueous humor flow rate in 15 dogs. Corneas were loaded with fluorescein by topical application, and corneal and aqueous humor fluorescein concentrations were measured five, 6.5, and eight hours after application. Concentration-versus-time plots were generated, and slopes and ratios of the fluorescein concentration in the cornea and aqueous humor from these graphs were used to calculate flow rates. Calculations were performed by use of automated software provided with the fluorophotometer and by manual computation, and the two calculation methods were compared. RESULTS: The protocol established for the five dogs resulted in semilogarithmic and parallel decay of corneal and aqueous humor concentrations. Manually calculated mean ± SD aqueous humor flow rates for left, right, and both eyes were 5.58 ± 2.42, 4.86 ± 2.49, and 5.22 ± 1.87 μl/min, respectively, whereas corresponding flow rates calculated by use of the automated software were 4.54 ± 3.08, 4.54 ± 3.10, and 4.54 ± 2.57 μl/min, respectively. Values for the left eye were significantly different between the two computation methods. CONCLUSIONS AND CLINICAL RELEVANCE: Aqueous humor flow rates can be determined in dogs, using fluorophotometry. This technique can be used to assess pathologic states and medical and surgical treatments that alter aqueous humor dynamics.
Dr D.A. Ward, The Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901, USA
2.6 Aqueous humor dynamics (Part of: 2 Anatomical structures in glaucoma)