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Home / Equine Research Bank / Equine Vet J / Comparison of four tonometers in the measurement of intraocu...
Equine veterinary journal2022; doi: 10.1111/evj.13911

Comparison of four tonometers in the measurement of intraocular pressure in healthy horses.

Abstract: Measurement of the intraocular pressure (IOP) is a useful diagnostic tool in equine ophthalmology. Handheld tonometers, such as Tonovet and Tonovet Plus (rebound), Tono-Pen AVIA Vet (applanation), and Kowa HA-2 (applanation using the Goldmann methodology) are used to obtain IOP measurements in veterinary medicine. Objective: To compare and evaluate the accuracy of four handheld tonometers in measuring IOP using different methodologies in healthy horses. Methods: In vivo experiment and cross-sectional survey of healthy horses. Methods: Intraocular pressure was measured in 72 eyes of 36 horses. An in vivo study was conducted on sedated horses to compare the real IOP values obtained using manometry versus those obtained using tonometry, and a field study was conducted on unsedated healthy horses with normal eyes to measure the IOP values using different tonometers. Results: In the in vivo study, the mean IOP values using ocular manometry was 24.9 ± 4.0 mmHg (range, 20.0-30.0 mmHg). The mean IOP values using tonometry were: Tonovet, 25.7 ± 5.8 mmHg (range 19.5-33.0 mmHg); Tonovet Plus, 24.8 ± 7.1 mmHg (range 13.2-33.2 mmHg); Tono Pen AVIA Vet, 19.2 ± 4.7 mmHg (range 13.1-26.5 mmHg); and Kowa Ha-2, 24.1 ± 1.2 mmHg (range 22.8-25.8 mmHg). In the field study, the IOP values were: Tonovet, 30.7 ± 5.6 mmHg (range 21.7-38.0 mmHg); Tonovet Plus, 29.6 ± 6.7 mmHg (range 16.2-38.6 mmHg); Tono-Pen AVIA Vet, 27.3 ± 5.8 mmHg (range 14.6-37.1 mmHg); and Kowa HA-2, 23.4 ± 2.2 mmHg (range 20.2-28.7 mmHg). Conclusions: This study included only healthy horses and a limited number of animals in the in vivo study. Conclusions: There was a strong correlation between the IOP values and manometry for all tonometers. IOP should be estimated using the same tonometer over time, and the bias of the tonometer used, such as overestimation (rebound tonometer) and underestimation (applanation tonometer), should be acknowledged. A normal reference value for each tonometer should be established in horses. Unassigned: La medición de la presión intraocular (IOP) juega un rol crucial en el diagnóstico de oftalmopatías que pueden llevar a la ceguera en caballos. Los tonómetros portátiles, tales como Tonovet y Tonovet Plus (de rebote), Tono-Pen AVIA Vet (aplanación), and Kowa HA-2 (aplanación usando el método Goldmann), son usados para obtener las mediciones de IOP en medicina veterinaria. Objective: Comparar y evaluar la precisión de cuatro tonómetros portátiles para medir IOP usando distintas metodologías en caballos sanos. DISEÑO DEL ESTUDIO: Experimento in vivo y estudio transversal de caballos sanos. MÉTODOS: IOP fue medida en 72 ojos de 36 caballos. Un estudio in vivo fue llevado a cabo en caballos sedados para comparar los valores reales de IOP obtenidos usando manometría versus aquellos obtenidos usando tonometría, y un estudio de campo fue llevado a cabo en caballos sanos no sedados con ojos normales para medir los valores de IOP obtenidos con distintos tonómetros. Results: En el estudio in vivo, los valores promedio de IOP usando manometría ocular fueron 24.9 ± 4.0 mmHg (rango, 20.0-30.0 mmHg). Los valores de IOP promedio usando tonometría fueron: Tonovet, 25.7 ± 5.8 mmHg (rango 19.5-33.0 mmHg); Tonovet Plus, 24.8 ± 7.1 mmHg (rango 13.2-33.2 mmHg); Tono Pen AVIA Vet, 19.2 ± 4.7 mmHg (rango 13.1-26.5 mmHg); and Kowa Ha-2, 24.1 ± 1.2 mmHg (rango 22.8-25.8 mmHg). En el estudio de campo, los valores de IOP fueron: Tonovet, 30.7 ± 5.6 mmHg (rango 21.7-38.0 mmHg); Tonovet Plus, 29.6 ± 6.7 mmHg (rango 16.2-38.6 mmHg); Tono-Pen AVIA Vet, 27.3 ± 5.8 mmHg (rango 14.6-37.1 mmHg); and Kowa HA-2, 23.4 ± 2.2 mmHg (rango 20.2-28.7 mmHg). Unassigned: Este estudio incluyo solo caballos sanos y un número limitado en el estudio in vivo. Conclusions: Hubo una fuerte correlación entre los valores de IOP por manometría con todos los tonómetros. IOP debería estimarse usando el mismo tonómetro a través de tiempo, y el sesgo del tonómetro usado, como la sobre estimación (tonómetro de rebote) y la baja estimación (tonómetro por aplanación), debería reconocerse. Valores normales para cada tonómetro deberían establecerse para el caballo.
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Publication Date: 2022-12-20 PubMed ID: 36537844DOI: 10.1111/evj.13911Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study has evaluated the accuracy of four different handheld tonometers in measuring intraocular pressure (IOP) in healthy horses. The results showed a strong correlation between IOP values from tonometers and manometry. However, it suggested maintaining consistency with the type of tonometer used over time due to inherent biases like overestimation and underestimation in different tonometers.

About the Study

  • The study involved a comparison of four different handheld tonometers. These were Tonovet and Tonovet Plus (rebound types), Tono-Pen AVIA Vet (an applanation tonometer), and Kowa HA-2 (an applanation tonometer using the Goldmann methodology).
  • The IOP values were compared in two experiments – an in vivo experiment on sedated horses and a cross-sectional study on unsedated healthy horses with normal eyes.

Study Results

  • In the in vivo study, the mean IOP value obtained with ocular manometry was 24.9 ± 4.0 mmHg. The values obtained using tonometry were similar for all tonometers except for the Tono Pen AVIA Vet, which showed slightly lower mean IOP values.
  • In the field study on unsedated healthy horses, the IOP values obtained with different tonometers varied, but they were well within the range of healthy IOP readings.
  • Strong correlation was observed between IOP values obtained with tonometers and manometry.

Conclusions

  • This research is instrumental in determining the efficacy and accuracy of different tonometers used in equine ophthalmology.
  • However, the study suggests using the same tonometer consistently over time due to potential biases, such as overestimation by rebound tonometers and underestimation by applanation tonometers.
  • Establishing a normal reference value for each tonometer is necessary to account for the variations that could arise due to the methodology used.

Study Limitations

  • The study only included healthy horses, which may not accurately represent the range of IOP values in horses with certain ophthalmological conditions.
  • A limited number of animals were used in the in vivo study, which could have impacted the overall findings of the research.

Cite This Article

APA
Angeluci GC, Ricci CL, Passareli JVGC, Estanho GJG, Oliveira AS, Santos SGA, Giuffrida R, Rodrigues M, Andrade SF. (2022). Comparison of four tonometers in the measurement of intraocular pressure in healthy horses. Equine Vet J. https://doi.org/10.1111/evj.13911

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Angeluci, Gismelli C
  • Department of Animal Science, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Ricci, Cláudia L
  • Department of Animal Science, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Passareli, João V G C
  • Department of Animal Science, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Estanho, Giovana J G
  • Department of Animal Science, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Oliveira, Adriana S
  • Faculty of Veterinary Medicine, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Santos, Stephany G A
  • Faculty of Veterinary Medicine, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Giuffrida, Rogério
  • Department of Animal Science, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Rodrigues, Mirian
  • Faculty of Veterinary Medicine, UNOESTE, Presidente Prudente, São Paulo, Brazil.
Andrade, Silvia F
  • Department of Veterinary Ophthalmology, Veterinary Hospital, UNOESTE, Presidente Prudente, São Paulo, Brazil.

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