Ocular Examinations and Investigation of Intraocular Pressure, Tear Production, Central Corneal Thickness, and Corneal Touch Threshold in a Captive Flock of Atlantic Puffins (Fratercula arctica)

• Published in: Journal of avian medicine and surgery Vol. 34; no. 2; pp. 123 - 131
• Main Authors: Westmoreland, Lori S. H, Hadfield, Catherine A, Clayton, Leigh A, Atkins, Rosalie M, Hyman, Jennifer A, Rossi, Benjamin H
• Format: Journal Article
• Language: English
• Published: United States Association of Avian Veterinarians 21-07-2020
• Subjects: Alcidae; Analysis; Animals; Atlantic puffin; Auks; avian; Birds; Birds - physiology; Cataracts; Cornea - physiology; corneal sensitivity; corneal thickness; Female; Fratercula arctica; Information management; Intraocular Pressure; Investigations; Male; ophthalmic; ORIGINAL STUDIES; Original Study; phenol red thread tear test; Reference Values; Tears - physiology; Tonometry, Ocular - veterinary; Touch - physiology; Fratercula arctica; corneal thickness; Alcidae; intraocular pressure; Atlantic puffin; ophthalmic; corneal sensitivity; phenol red thread tear test; avian
• ISSN: 1082-6742; 1938-2871
• DOI: 10.1647/1082-6742-34.2.123

Ocular examinations were completed on a group of 10 Atlantic puffins (Fratercula arctica), 5 males and 5 females that ranged in age from 8 months to older than 30 years. The exams consisted of intraocular pressure/rebound tonometry, tear production/phenol red thread test, central corneal thickness/ultrasound pachymetry, and corneal sensitivity/esthesiometry. On ocular examination, there were no corneal abnormalities observed. Bilateral cataracts were diagnosed in 8 puffins, 6 of which were considered incipient, focal subcapsular opacities. One bird had hypermature cataracts and was removed from the study and excluded from data analysis; the other birds had no evidence of ophthalmic pathology that would interfere with diagnostic results (n = 9). All results for 9 birds were included in the study, with the exception of 1 puffin's tear production, which was too low for accurate assessment and was excluded from data analysis. There were no significant differences between right and left eye measurements for intraocular pressure, corneal thickness, and corneal sensitivity. The median intraocular pressure for both eyes (OU) was 13 mm Hg with an interquartile range [IQR] of 12–15 mm Hg. The median corneal thickness OU was 241 µm, IQR 233–248 µm. The median corneal sensitivity OU was 1.13 cm, IQR 0.81–1.50 cm. There was a significant difference between right and left eye measurements for tear production (right eye median, 7.5 mm/15 s, IQR 6.5–9.3 mm/15 s; and left eye median, 5.0 mm/15 s, IQR 4.0–7.3 mm/15 s) (P= .03), with the right eye producing more tears than the left. However, 1 puffin was determined to be an outlier, and when removed, there was no longer a significant difference (OU median, 7.0 mm/15 s, IQR 4.6–8.0 mm/15 s) (P = .38). There was no significant difference between sex and intraocular pressure, tear production, and corneal sensitivity. However, there was a significant difference between sex and corneal thickness (P = .02), with males (left eye median, 249 µm, IQR 241–249 µm) having thicker corneas than females (left eye median, 236 µm, 234–238 µm). Although sample size precluded statistical testing, there appeared to be an association between opacities and increasing age. There were no associations between age and intraocular pressure, tear production, or corneal thickness. There was a moderate correlation between age and corneal sensitivity, with older birds showing decreased corneal sensitivity (r = –0.57). Although the sample size of 9 birds was small, these findings provide preliminary ranges for ocular parameters of Atlantic puffins.