Central corneal thickness and intraocular pressure in captive black-footed penguins (Sphenicus dermersus)

Abstract

Objective To determine the central corneal thickness (CCT) by ultrasonic pachymetry and the effect of these values on the measurements of intraocular pressures (IOP) with rebound tonometry (TonoVet®) in a captive flock of black-footed penguins (Spheniscus dermersus). Variations in CCT by age and weight, and variations in IOP by age were compared.

Animal studied Both eyes of 18 clinically normal black-footed penguins (Spheniscus dermersus) were used.

Procedure The IOP was measured by the TonoVet® in both eyes of all the penguins. CTT measurements were performed 5 min later in all eyes using an ultrasound pachymeter.

Results The mean IOP values ± SD were 31.77 ± 3.3 mm Hg (range of mean value: 24–38). The mean CCT values were 384.08 ± 30.9 μm (range of mean value: 319–454). There was no correlation between IOP and CCT values (P = 0.125). There was no difference in CCT measurements by age (P = 0.122) or weight (P = 0.779). A correlation was observed (P = 0.032) between IOP values and age. The coefficient of correlation was negative (ρ = −0.207).

Conclusions Ultrasound pachymetry has shown to be a reliable and easy technique to measure CCT in penguins. No correlation was observed between IOP and CCT values in this study. IOP showed a significant but weak decrease as age increased in the black-footed penguin.