Fachbereich Veterinärmedizin



    Intraocular pressure measurements in cattle, sheep and goats with two different tonometers (2016)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Peche, N. (WE 20)
    Eule, J.C. (WE 20)
    Veterinary Ophthalmology; 19(5) — S. E20
    ISSN: 1463-5216
    Klinik für kleine Haustiere

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    Abstract / Zusammenfassung

    Purpose: To investigate normal intraocular pressure (IOP) values of cattle, sheep and goats
    with two different tonometers (TonoVet [TV] and TonoPen AVIA [TPA]). Calibration of
    the tonometers was performed for cattle and sheep eyes. Methods: Twenty healthy cattle,
    sheep and goats each underwent slit-lamp biomicroscopy and IOP readings of both eyes
    were taken with the two different tonometers (TV in setting ‘d’). IOP results were statistically
    analyzed (Wilcoxon-test, P ≤ 0.05). For calibration purposes the IOP was preset from 5
    to 60 mmHg in steps of 5 mmHg in 10 bovine and eight ovine freshly enucleated eyes from
    slaughtered animals. For every interval, readings were taken with both tonometers and compared
    to the manometrically controlled IOP (Mann–Whitney-U-test, P ≤ 0.05; Bland–
    Altman; regression analysis). Results: In cattle, sheep and goats median IOP (min–max)
    obtained with the TV was 23 mmHg (12–40 mmHg), 11 mmHg (7–20 mmHg) and
    23 mmHg (9–37 mmHg) and with the TPA 16 mmHg (8–27 mmHg), 10 mmHg (5–
    18 mmHg) and 13 mmHg (4–25 mmHg), respectively. There were statistically significant
    differences between the readings taken with the TV and TPA in all species (Wilcoxon-test,
    P ≤ 0.05). All measurements obtained with the TV and TPA within the calibration procedure differed statistically significantly from the manometrically controlled IOP (Mann–Whitney-U-test, P ≤ 0.05). For both instruments regression formulas were calculated to correct the measurements (TV: cattle mano = (TV + 5.392)/1.226, r2 = 0.98; sheep mano = (TV + 2.5601)/0.9816, r2 = 0.98;TPA: cattle mano = (TPA + 0.7864)/0.7141, r2 = 0.92; sheep mano= (TPA + 1.1840)/0.6337, r2 = 0.98). Conclusion: In consideration of the specific regression formula both tonometers can be used effectively to assess the intraocular pressure in ruminants.