Central corneal thickness and intraocular pressure in captive black‐footed penguins (<scp>S</scp>pheniscus dermersus)

Gonzalez-Alonso-Alegre, Elisa M.; Martínez‐Nevado, Eva; Caro-Vadillo, Alicia; Rodríguez-Álvaro, Alfonso

doi:10.1111/vop.12206

Cited by 18 publications

(18 citation statements)

References 25 publications

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“…Considering the differences in the present study between young and adult birds, a study in three week old chickens, showed IOP values of 17.51±0.13 mmHg, that did not differ significantly with broiler and layer chickens lines (Prashar et al, 2007), but again it should be noted that these are not water birds. In one study of captive black-footed penguins (Spheniscus dermersus) tonometry showed a much higher IOP (31.77±3.3 mmHg) than in our study (Gonzales-Alonso-Alegre et al, 2015), and a later publication of ocular findings and reference values in penguins showed IOP measured with the Tonovet tonometer "d" calibration to be 29.1±7.16 mmHg in Macaroni and 24.1±5.09 mmHg in Rockhopper penguin, both higher than in swans evaluated here (Bliss et al, 2015). A more recent research study on IOP in ducks and geese showed the average IOP to be 10.2±2.2 mmHg in ducks and 9.1±2.0 mmHg in geese, measured with TonoVet tonometer (calibrated at the "d" setting as in the current study) giving results similar to those in the present study (Mood et al, 2016).…”

Section: Methodscontrasting

confidence: 81%

Tear production and intraocular pressure values in clinically normal eyes of whooper swans (Cygnus cygnus)

Kovaļčuka¹,

Boiko²,

Williams³

2018

Open Vet J.

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The objective of this study was to determine the normal range of tear production and values of intraocular pressure (IOP) in clinically normal eyes of whooper swans (Cygnus cygnus). A total of 86 birds: 81 cygnets (6-10 weeks old) and 5 moulting – adult swans (3-6 years old) were examined in this study. Both eyes of all birds underwent a complete ophthalmic examination, including evaluation of tear production with the phenol red thread test (PRTT) and the assessment of the IOP by rebound tonometry, employing the TonoVet® device. The mean ± standard deviation of PRTT values were as follows: all cygnets (81) 22.59±3.48 mm/15s, male cygnets (45) 22.64±3.54 mm/15s, female cygnets (36) 22.53±3.44 mm/15s. IOP was as follows: all cygnets 11.30±3.55 mmHg, male cygnets 10.93±3.56 mmHg, female cygnets 11.74±3.50 mmHg. No statistically significant differences between right and left eye and between female and male cygnets were found for IOP and PRTT values. This study provides the reference values for the PRTT and IOP in healthy whooper swan cygnets, showing that PRTT determination of the tear production and rebound tonometry to evaluate the IOP methods are practical methods for ophthalmic examination in swans.

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Section: Methodscontrasting

confidence: 81%

Tear production and intraocular pressure values in clinically normal eyes of whooper swans (Cygnus cygnus)

Kovaļčuka¹,

Boiko²,

Williams³

2018

Open Vet J.

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“…The aim of the systematic review was to collect typical IOPs for healthy adult species of vertebrates; therefore, some aspects of the variations in IOP within each group of vertebrates were not included in the study. While in healthy animals the IOP is generally not significantly different in the left and right eye [ 40 , 41 , 43 , 53 , 56 – 59 , 64 – 66 , 69 , 74 – 76 , 79 , 85 , 88 , 91 , 92 , 98 , 103 , 111 , 114 , 114 , 117 , 122 – 127 , 132 ] or in males and females [ 41 , 43 , 56 , 58 , 63 , 65 , 69 , 74 , 75 , 79 , 85 , 88 , 91 , 92 , 103 , 114 , 121 – 124 , 126 , 132 , 133 ], it has been found to change with position in flamingos and bats. [ 59 , 60 , 114 ].…”

Section: Discussionmentioning

confidence: 99%

Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

2016

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In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as , where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma.

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“…The TonoVet ® setting can be ‘d’ (dog/cat), ‘h’ (horse), or ‘p’ (undefined). In avian studies comparing ‘d’ and ‘p’, ‘d’ is found to read higher than ‘p’, and in studies comparing ‘d’ and ‘h’, results have varied . Most studies in avian ophthalmology have used the ‘d’ setting .…”

Section: Discussionmentioning

confidence: 99%

“…In avian studies comparing ‘d’ and ‘p’, ‘d’ is found to read higher than ‘p’, and in studies comparing ‘d’ and ‘h’, results have varied . Most studies in avian ophthalmology have used the ‘d’ setting . Studies with captive black‐footed penguins and Humboldt penguins have found the mean IOP with ‘d’ setting to be between 20.3 and 31.7 mmHg .…”

Section: Discussionmentioning

confidence: 99%

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Comparison of anterior segment health in wild and captive common murres

Freeman

Fiorello²,

Murray

2017

Veterinary Ophthalmology

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Central corneal thickness and intraocular pressure in captive black‐footed penguins (Spheniscus dermersus)

Abstract: 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.

Cited by 18 publications

References 25 publications

Tear production and intraocular pressure values in clinically normal eyes of whooper swans (<i>Cygnus cygnus</i>)

Tear production and intraocular pressure values in clinically normal eyes of whooper swans (<i>Cygnus cygnus</i>)

Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

Comparison of anterior segment health in wild and captive common murres

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