Comparison of three rebound tonometers in normal and glaucomatous dogs

Hodgson, Kimberly J.; Harman, Christine; Bajric, Shayla; Cabble, Ava; Anderson, Andy; Palanivel, Hemalatha; Taylor, David A.; Komàromy, András M.

doi:10.1111/vop.13043

Cited by 8 publications

(28 citation statements)

References 35 publications

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“…Various studies have evaluated and calibrated other tonometers in porcine eyes, such as the TonoVet, Tono-Pen Vet, and TAO1, which showed that the TonoVet appeared to closely approximate true IOP, whereas the Tono-Pen and TAO1 underestimated true IOP. 5,6 The Tono-Vera® Vet has been evaluated in normal and glaucomatous dogs, 7 however, there is no study to the best of our knowledge that evaluates the use of the Tono-Vera® Vet in pigs. Therefore, the purpose of this study was to calibrate this device for use in porcine eyes and to determine which settings are most appropriate.…”

mentioning

confidence: 99%

Calibration of a novel rebound tonometer (Tono‐Vera® vet) in the porcine eye

Mills

Liu

Emelogu

et al. 2023

Veterinary Ophthalmology

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Objective Porcine models of ocular disease are becoming increasingly utilized. A recently commercialized ocular tonometer, the Reichert Tono‐Vera® Vet, has not been evaluated for use in pigs. The purpose of this study was to calibrate this device for use in porcine eyes and to determine which settings are most appropriate for use in pigs. Procedure The anterior chambers of five freshly enucleated normal porcine eyes were cannulated then connected to a reservoir of balanced salt solution and a physiologic monitor. Triplicate measurements were obtained with the four available settings: dog, cat, horse, and rabbit at intraocular pressures ranging from 5– to 80 mmHg. Bland–Altman analysis was utilized to determine bias and 95% limits of agreement for each setting. Results There was a strong positive linear regression trend for all settings (dog r2 = 0.986, horse r2 = 0.947, cat r2 = 0.977, and rabbit r2 = 0.982). The linear regression equations for the dog, horse, cat, and rabbit setting were y = 1.0168x – 2.6128, y = 0.8743x – 3.4959, y = 0.9394x – 7.3188, and y = 1.1082x – 3.4077. The average bias and 95% limits of agreement for dog, horse, cat, and rabbit settings were − 2.00, −8.32, −9.58, and 0.57 mmHg, and (−7.52, 3.53), (−19.00, 2.37), (−16.66, −2.50), and (−7.79, 8.93), in mmHg. Conclusion The Tono‐Vera® Vet dog setting was most accurate and precise setting compared to true intraocular pressures. This setting is likely to be appropriate for in vivo use in pigs, with the appropriate correction formula applied.

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mentioning

confidence: 99%

Calibration of a novel rebound tonometer (Tono‐Vera® vet) in the porcine eye

Mills

Liu

Emelogu

et al. 2023

Veterinary Ophthalmology

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“…This technology assesses the velocity characteristics of a small probe propelled toward the cornea and gently impacting its surface; the speed of probe deceleration correlates with IOP 1 . Distance and angle of the probe relative to the corneal surface are critical for accurate IOP measurements 1–6 …”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, probe angle indicators help the operator to keep the probe angle within the required ±15 degrees of horizontal 4 . A recent study demonstrated a strong agreement between the ICare® Tonovet Plus® rebound tonometer (TVP; Icare Finland Oy) and the Tono‐Vera® Vet, suggesting that it also reflects true IOP canine values 4 . In another study, the Tono‐Vera® Vet dog setting was accurate when used on ex vivo pig eyes and compared to direct manometry 7 …”

Section: Introductionmentioning

confidence: 99%

“…When using the ActiView™ positioning system, operators can select 1 (Quick) or 3+ measurements. When 3+ is selected, the Tono‐Vera® Vet automatically averages three readings upon proper XYZ alignment of the instrument without pushing any buttons 4 . When 1 measurement is selected Tono‐Vera® Vet only takes a single reading instead of averaging three 4 .…”

Section: Introductionmentioning

confidence: 99%

“…When 3+ is selected, the Tono‐Vera® Vet automatically averages three readings upon proper XYZ alignment of the instrument without pushing any buttons 4 . When 1 measurement is selected Tono‐Vera® Vet only takes a single reading instead of averaging three 4 . The instrument can also be used with the ActiView™ positioning system turned off (Manual Mode).…”

Section: Introductionmentioning

confidence: 99%

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Efficacy of the positioning system when measuring canine intraocular pressures with the Reichert® Tono‐Vera® Vet rebound tonometer

Cabble,

Bajric,

Kapeller

et al. 2023

Veterinary Ophthalmology

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ObjectiveTo compare intraocular pressure (IOP) measurements in dogs taken with the Reichert® Tono‐Vera® Vet rebound tonometer with and without the automatic positioning system.Animals StudiedMeasurements were taken on 49 eyes from 26 Beagle‐derived dogs with variable genetics—four non‐glaucomatous and 22 ADAMTS10‐mutant dogs affected with different stages of open‐angle glaucoma. Seventeen of the 26 dogs were measured 2–4 times on different days with variable intervals since IOP‐lowering medications were administered.ProceduresIn each dog, tonometry was performed with the Tono‐Vera® Vet using three different methods in a randomized order: (Method 1) Average of three readings with an automatic positioning system; (Method 2) one reading with an automatic positioning system; and (Method 3) average of three readings obtained without the automatic positioning system. Statistical analyses included one‐way ANOVA, Tukey pairwise comparisons, and Bland–Altman plots (MiniTab®).ResultsWith each of the three tonometry methods, 116 measurements were taken, resulting in 348 total IOP measurements with a range of 12.8–49.9 mmHg. The means and standard deviations for each method were 25.4 ± 6.9 mmHg (Method 1), 26.0 ± 7.2 mmHg (Method 2), and 26.9 ± 7.7 mmHg (Method 3), with no significant differences (p = .27). Mean IOP variances were also not significantly different between tonometry methods (p = .24 to .78).ConclusionsBecause mean IOPs and their standard deviations were not statistically different between the three tonometry methods, we conclude that Tono‐Vera® Vet measurements conducted without the aid of the positioning system still provide reliable results.

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Comparing the intraocular pressure values obtained with a rebound tonometer (TONOVET Plus) and an indentation tonometer (IOPvet) in dogs with and without ocular disease

Michaud,

Lesne

2024

Veterinary Record

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BackgroundThis study aimed to compare the intraocular pressure (IOP) values obtained from two groups of dogs using the IOPvet indentation tonometer to those obtained from the same dogs using an established rebound tonometer (TONOVET Plus).MethodsTonometry was performed on 36 dogs with ocular diseases (70 eyes; group A) and 25 healthy dogs (49 eyes; group B). First, the TONOVET Plus rebound tonometer was used. Then, one drop of oxybuprocaine hydrochloride was applied to each eye, and 1 minute later, the IOP was estimated using the IOPvet.ResultsThe IOPvet was safe, well tolerated and easy to use. The instrument had a high specificity (98.5%) for identifying IOPs of 20 mmHg or less. A lack of sensitivity (67.9%) was noted when evaluating eyes with an IOP between 20 and 30 mmHg. The sensitivity (33.3%) for identifying canine eyes with an IOP of greater than 30 mmHg (n = 24) was low.LimitationsThis study lacks manometric work, which would be hard to justify with client‐owned dogs. Quantitative numerical data were compared with qualitative values and the same investigator obtained readings using both tonometers without being masked.ConclusionsThe IOPvet is highly sensitive for assessing normal IOPs, but underestimation of higher IOPs can lead to poor diagnostics. Digital tonometers remain the best way to assess IOP in veterinary clinics.

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Comparison of three rebound tonometers in normal and glaucomatous dogs

Cited by 8 publications

References 35 publications

Calibration of a novel rebound tonometer (Tono‐Vera® vet) in the porcine eye

Calibration of a novel rebound tonometer (Tono‐Vera® vet) in the porcine eye

Efficacy of the positioning system when measuring canine intraocular pressures with the Reichert® Tono‐Vera® Vet rebound tonometer

Comparing the intraocular pressure values obtained with a rebound tonometer (TONOVET Plus) and an indentation tonometer (IOPvet) in dogs with and without ocular disease

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