Comparison of the Effects of Different TonoVet® Plus Modes on Intraocular Pressure Measurements in Healthy Domestic Pigeons (Columba livia)

Year 2026, Volume: 15 Issue: 1, 122 - 127, 28.02.2026

Eyüp Tolga Akyol , Büşra Aslan Akyol , Muharrem Erol

https://doi.org/10.53424/balikesirsbd.1809997

https://izlik.org/JA34BW66DM

Abstract

Objective: The aim of this study was to systematically evaluate Intraocular pressure (IOP) measurements in healthy, conscious domestic pigeons using the four available animal modes on the TonoVet® Plus device. Materials and Methods: Seventy eyes of 35 healthy pigeons were included in the study. IOP measurements were performed in conscious animals, without anesthesia, using the four modes of the TonoVet® Plus device in a randomized order Results: Measurement mode had a statistically significant effect on IOP (p < 0.05). Mean IOP ranged from 8.59±2.22 mmHg for the Cat mode to 15.57±2.04 mmHg for the Rabbit mode. All modes demonstrated excellent reliability (ICC > 0.88), with the Cat mode having the highest (ICC=0.931) and the Rabbit mode the lowest (ICC=0.882). Compared to the calibrated reference value in the literature, the Rabbit mode provided the result closest to the lower limit of the reference range, while the most reliable Cat mode significantly underestimated IOP. Conclusion: None of the available modes in TonoVet® Plus are ideal for pigeons, and mode selection significantly influences the results. The Cat mode, with its highest reliability, is preferred for monitoring IOP changes, while the Rabbit mode, with its highest apparent accuracy, is preferred for scanning against the reference range. However, in both cases, results should be interpreted cautiously within the limitations of the mode. Direct manometric calibration of TonoVet® Plus for pigeons and the development of a species-specific mode are needed.

Keywords

Avian , Columba livia , Glaucoma , Intraocular Pressure , Rebound Tonometry , TonoVet Plus

Ethical Statement

Institution: Balikesir University Animal Experiments Local Ethics Committee (BAUNHADYEK) Date: 07.08.2025 Approval no: 2025/7-13

Supporting Institution

None.

Thanks

None.

Sağlıklı Evcil Güvercinlerde (Columba livia) Farklı TonoVet® Plus Modlarının Göz İçi Basıncı Ölçümlerine Etkilerinin Karşılaştırılması

https://izlik.org/JA34BW66DM

Abstract

Amaç: Bu çalışma, TonoVet® Plus rebound tonometresinin dört farklı modu (Kedi, Köpek, At ve Tavşan) kullanılarak sağlıklı, bilinçli evcil güvercinlerde elde edilen Göz İçi Basıncı'nı (GİB) sistematik olarak karşılaştırmayı ve her modun mod içi ölçüm güvenilirliğini belirlemeyi amaçlamaktadır. Gereç ve Yöntem: Çalışmaya 35 sağlıklı güvercinin 70 gözü dahil edildi. GİB ölçümleri, anestezi uygulanmadan, TonoVet® Plus cihazının dört modu kullanılarak, rastgele bir sırayla, bilinçli hayvanlarda gerçekleştirildi. Bulgular: Ölçüm modunun GİB üzerinde istatistiksel olarak anlamlı bir etkisi vardı (p < 0,05). Ortalama GİB, Kedi modu için 8,59±2,22 mmHg ile Tavşan modu için 15,57±2,04 mmHg arasında değişti. Tüm modlar mükemmel güvenilirlik gösterdi (ICC > 0,88), Kedi modu en yüksek (ICC = 0,931) ve Tavşan modu en düşük (ICC = 0,882) değere sahipti. Literatürdeki kalibre edilmiş referans değerleriyle karşılaştırıldığında, Tavşan modu referans aralığının alt sınırına en yakın sonucu verirken, en güvenilir Kedi modu GİB'yi önemli ölçüde düşük tahmin etmiştir. Sonuç: TonoVet® Plus'taki mevcut modların hiçbiri güvercinler için ideal değildir ve mod seçimi sonuçları önemli ölçüde etkilemektedir. En yüksek güvenilirliğe sahip Kedi modu, GİB değişikliklerini izlemek için tercih edilebilirken, en yüksek görünür doğruluğa sahip Tavşan modu, referans aralığı ile tarama yapmak için tercih edilebilir. Ancak, her iki durumda da sonuçlar modun sınırları dahilinde dikkatle yorumlanmalıdır. TonoVet® Plus'ın güvercinler için doğrudan manometrik kalibrasyonu ve türe özgü bir modun geliştirilmesi gerekmektedir.

Keywords

Kuş , Columba livia , Glokom , Göz İçi Basıncı , Rebound Tonometri , TonoVet Plus

Ethical Statement

Kurum: Balıkesir Üniversitesi Hayvan Deneyleri Yerel Etik Kurulu (BAUNHADYEK) Tarih: 07.08.2025 Onay No: 2025/7-13

Supporting Institution

Yok.

Thanks

Yok.

References

• Ansari Mood, M., Rajaei, S. M., Hashemi, S. S. G., & Williams, D. L. (2016). Measurement of intraocular pressure in the domestic pigeon ( Columbia livia ). Journal of Zoo and Wildlife Medicine, 47(3), 935-938. https://doi.org/10.1638/2015-0102.1.
• Barbosa, S. F., Raposo, A. C. S., Dórea Neto, F. A., Araujo, N. L. L. C., Oliveira, M. M. S., & Oriá, A. P. (2022). TonoVet Plus®: Higher reliability and repeatability compared with Tono‐Pen XL™ and TonoVet® in rabbits. Veterinary Ophthalmology, 25(4), 272-281. https://doi.org/10.1111/vop.12981.
• Baudouin, C., & Gastaud, P. (1994). Influence of topical anesthesia on tonometric values of intraocular pressure. Ophthalmologica, 208(6), 309–313. https://doi.org/10.1159/000310527.
• Chan-Ling, T., Efron, N., & Holden, B. A. (1985). Diurnal variation of corneal thickness in the cat. Investigative ophthalmology & visual science, 26(1), 102–105.
• Chard, R.D., Gundlach, R.H. (1938). The structure of the eye of the homing pigeon. Journal of Comparative Psychology. 25, 249–272. https://doi.org/10.1037/h0061438
• Gloe, S., Rothering, A., Kiland, J. A., & McLellan, G. J. (2019). Validation of the Icare® TONOVET plus rebound tonometer in normal rabbit eyes. Experimental Eye Research, 185, 107698. https://doi.org/10.1016/j.exer.2019.107698.
• Herbig, L. E., & Eule, J. C. (2015). Central corneal thickness measurements and ultrasonographic study of the growing equine eye. Veterinary ophthalmology, 18(6), 462–471. https://doi.org/10.1111/vop.12252
• Jorge, J. M. M., González-Méijome, J. M., Queirós, A., Fernandes, P., & Parafita, M. A. (2008). Correlations between corneal biomechanical properties measured with the ocular response analyzer and ICare rebound tonometry. Journal of Glaucoma, 17(6), 442–448. https://doi.org/10.1097/IJG.0b013e31815f52b8.
• Karimi, V., Asadi, F., Rajaei, S. M., & Golabdar, S. (2020). Intraocular pressure measurements using rebound tonometry in eight different species of companion birds. Journal of Avian Medicine and Surgery, 34(4), 338-342. https://doi.org/10.1647/1082-6742-34.4.338.
• Kovalcuka, L., Mālniece, A., & Vanaga, J. (2024). Comparison of Tonovet® and Tonovet plus® tonometers for measuring intraocular pressure in dogs, cats, horses, cattle, and sheep. Veterinary World, 17(2), 384–388. https://doi.org/10.14202/vetworld.2024.384-388.
• Lim, J., Kang, S., Park, S., Park, E., Nam, T., Jeong, S., & Seo, K. (2019). Intraocular pressure measurement by rebound tonometry (TonoVet) in normal pigeons (Columba livia). Journal of Avian Medicine and Surgery, 33(1), 46-52. https://doi.org/10.1647/2017-329.
• Nakakura, S. (2018). Icare® rebound tonometers: Review of their characteristics and ease of use. Clinical Ophthalmology, Volume 12, 1245–1253. https://doi.org/10.2147/OPTH.S163092.
• Park, S., Kang, S., Lim, J., Park, E., Nam, T., Jeong, S., & Seo, K. (2017). Ultrasound biomicroscopy and tonometry in ophthalmologically normal pigeon eyes. Veterinary Ophthalmology, 20(5), 468–471. https://doi.org/10.1111/vop.12450.
• Reuter, A., Müller, K., Arndt, G., & Eule, J. C. (2011). Reference intervals for intraocular pressure measured by rebound tonometry in ten raptor species and factors affecting the intraocular pressure. Journal of Avian Medicine and Surgery, 25(3), 165–172. https://doi.org/10.1647/2009-056.1.
• Underwood, H., Steele, C. T., & Zivkovic, B. (2001). Circadian organization and the role of the pineal in birds. Microscopy Research and Technique, 53(1), 48–62. https://doi.org/10.1002/jemt.1068.
• Wang, X., & Wu, Q. (2013). Normal corneal thickness measurements in pigmented rabbits using spectral‐domain anterior segment optical coherence tomography. Veterinary Ophthalmology, 16(2), 130-134. https://doi.org/10.1111/j.1463-5224.2012.01041.x
• Wolfel, A. E., Pederson, S. L., Cleymaet, A. M., Hess, A. M., & Freeman, K. S. (2018). Canine central corneal thickness measurements via Pentacam‐HR®, optical coherence tomography (Optovue iVue®), and high‐resolution ultrasound biomicroscopy. Veterinary Ophthalmology, 21(4), 362–370. https://doi.org/10.1111/vop.12518
• Yönez, M. K., Erol, M., Erol, H., Atalan, G., Doğan, Z., & Kibar, M. (2022). Intraocular pressure measured by rebound tonometry in seven raptor species. Journal of the Hellenic Veterinary Medical Society, 73(2), 3929–3934. https://doi.org/10.12681/jhvms.21914.