Measurement of Tear Production and Intraocular Pressure in Healthy Captive Helmeted Guinea Fowl ( Numida meleagris )

We establish reference values of tear production by the phenol red thread test (PRTT) and intraocular pressure (IOP) by rebound tonometry in helmeted guinea fowl ( Numida meleagris ). Aqueous tear production and IOP were measured in 44 (22 males, 22 females) clinically normal captive helmeted guinea fowl. Birds were gently physically restrained in the sitting position without any pressure to the head or neck. In each bird, aqueous tear production was measured by placing phenol red threads in the superior conjunctival fornix, and IOP was measured by using a Tonovet rebound tonometer. Overall mean ± standard deviation (SD) values of PRTT and IOP of all eyes were 16.5 ± 1.3 mm/15 s (ranging from 14-18 mm/15 s) and 9.1 ± 0.9 mm Hg (ranging from 7-10 mm Hg), respectively. No significant differences were found in IOP or PRTT between males and females (P = .76; P = .83, respectively) or between the left and right eyes (P = .34 and .66, respectively) in the guinea fowl. Results of this study may be beneficial for the diagnosis and therapy of keratoconjunctivitis sicca, glaucoma, and uveitis in helmeted guinea fowl.