Reference values for selected ophthalmic tests of the blue-and-yellow macaw (Ara ararauna)

Abstract

The aim of this study was to establish reference values for selected ophthalmic diagnostic tests in healthy blue-and-yellow macaws. We investigated a total of 35 adult macaws (70 eyes) of undetermined sex and with an average weight of 1 kg, who were living in captivity in the Federal District, Brazil. Tear production using the Schirmer tear test (STT), normal conjunctival flora, intraocular pressure (IOP) using a rebound tonometer and horizontal palpebral fissure length (HPFL) were evaluated. In this study, 84.1% of samples were positive for microbial growth. Bacteria, fungi and yeasts were isolated, and Staphylococcus spp. (21.9%) and Bacillus spp. (26.8%) were the most frequently isolated microorganisms. The mean value for STT was 7.6±4.6mm/min in the right eye (OD) and 6.6±4.4mm/min in the left eye (OS) (median = 7,11±0,76mm/min). Mean IOP was 11.4±2.5mm Hg OD and 11.6±1.8mm Hg OS (median = 11.49±0.22mm Hg), prior to anesthesia, and 7.6±2.4mm Hg OD and 7.8±1.8mm Hg OS (median 7.71±0.08mmHg) after anesthesia. The IOP was significantly lower when the animals were under anesthesia as compared to when they were conscious (p≤0.05). Horizontal palpebral fissure length was 11.7±0.1mm OD and 11.8±0.1mm OS (median = 11.72±0.07mm). The STT showed a positive correlation with palpebral fissure measurement for this species. These selected ophthalmic reference values will be particularly useful in diagnosing pathological changes in the eyes of blue-and-yellow macaws.

Macroscopic morphological aspects, ecometry and rebound tonometry of the eye bulb in sloth (Bradypus variegatus)

“…In previous years, several investigations were carried out in order to determine the normal IOP of several species (Leiva et al 2006, Broadwater et al 2007, Blackwood et al 2010, Rusanen et al 2010, Pereira et al 2011, Falcão et al 2017, McDonald et al 2017, Hibbs et al 2018, however, there is no report describing normal values for sloths.…”

“…The RBT has been increasingly used in veterinary ophthalmology. TonoVet ® was designed its use in animals with small eyes (Falcão et al 2017). Its software is pre-programmed for six measurements, and the IOP is displayed as an average value of six consecutive central corneal rings.…”

“…The measurement of IOP by using RBT has been carried out in recent years, and standards for different species have been established with the use of TonoVet ® . Studies have been carried out on various domestic and wild species such as parrots (11.4mmHg), alpacas (14.2mmHg), donkey (25.5mmHg), cats (20.74mmHg), dogs (9.15mmHg), goats (7, 9mmHg), rabbits (9.51mmHg), bats (19.3mmHg) (Leiva et al 2006, Broadwater et al 2007, Blackwood et al 2010, Rusanen et al 2010, Pereira et al 2011, Falcão et al 2017, McDonald et al 2017, Hibbs et al 2018.…”

Use of endodontic paper points and Schirmer strips for measurement of tear flow in red-lored parrots (<em>Amazona autumnalis</em>)

“…This difficulty was also reported by Falcão et al when making measurements of tear flow with Schirmer strips in macaws. 3 The correct restraining of a bird is certainly important to accomplish an adequate measurement, since improper handling causes Figure 2. Measurement of tear flow in red-lored parrots using ABC Dental ® color paper tips # 30.…”

“…Determination of tear flow should be routinely included test in any eye examination. 3 Several ocular problems and diseases have been reported in psittacine birds, including peri-orbital lesions, 4 bilateral supra-orbital abscesses, 2 corneo-conjunctival dermoid cysts, 5 blepharo-conjunctivitis due to staphylococci, and fungal keratitis. 2 Also, exophthalmos secondary to squamous cell carcinoma in the infraorbital sinus has been found in an eclectus parrot (Eclectus roratus solomonensis) 6 or secondary to retrobulbar adenoma in an African gray parrot (Psittacus erithacus).…”