Validation of the Icare® TONOVET plus rebound tonometer in normal rabbit eyes

Self Cite

Objectives To determine the accuracy and precision of the Icare® TONOVET Plus rebound tonometer and the Tono‐Pen AVIA Vet™ applanation tonometer for intraocular pressure (IOP) measurement in normal ex vivo canine eyes and comparison to earlier models of these tonometers. Animals & procedures The anterior chambers of six normal dog eyes were cannulated ex vivo. IOP was measured with the TONOVET (TV01), TONOVET Plus, Tono‐Pen Vet™, and Tono‐Pen AVIA Vet™ at manometric IOPs ranging from 5 to 70 mm Hg. Data were analyzed by linear regression, ANOVA and Bland‐Altman plots. A P value ≤ .05 was considered significant. Results Intraocular pressure values obtained using the TONOVET Plus and TV01 were significantly more accurate than with the Tono‐Pen VET and Tono‐Pen AVIA Vet, particularly at higher IOPs (30‐70 mm Hg). Accuracy was not significantly different between any of the devices in the low to normal physiologic IOP range (5‐25 mm Hg). Level of precision was high for all devices, though the TONOVET Plus was more precise than the Tono‐Pen Vet in the 5‐25 mmHg range and the TV01 was more precise than the Tono‐Pen AVIA Vet over the whole IOP range. Conclusions All devices underestimated IOP, particularly at higher pressures. Rebound tonometers were more accurate over the full range of IOP tested and in the high IOP range; however, there were no significant differences in accuracy among devices in the physiologic IOP range. All tonometers can provide clinically useful IOP readings in dogs, but rebound and applanation tonometers should not be used interchangeably.

Section: Discussionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 95%

Validation and comparison of four handheld tonometers in normal ex vivo canine eyes

Minella

Kiland

Gloe

et al. 2020

Self Cite

“…Validation of this device has been reported not only for dogs but also for mice, monkeys, pigeons, birds of preys, and rabbits 12,15,26‐28 . Other rebound tonometers such as TONOVET‐Plus ® and SW‐500 ® have been recently used for laboratory animals 29,30 . IOP values measured with the rebound tonometer could be affected by differences in the biomechanical properties of the cornea between species 16,17,31 ; therefore, studies are being conducted to verify the accuracy of these instruments in each species.…”

Section: Discussionmentioning

confidence: 99%

Comparative intraocular pressure measurements using three different rebound tonometers through in an ex vivo analysis and clinical trials in canine eyes

Shim

Kang

Park

et al. 2020

Objective To evaluate the clinical relevance of intraocular pressure (IOP) measured with three different rebound tonometers in an ex vivo analysis and clinical trials in dogs. Animals and procedures Ex vivo analysis and clinical trials were performed separately. For the ex vivo analysis, eight enucleated eyes were obtained from four Beagle dogs. IOP values measured with TONOVET® (TV‐IOP), TONOVET‐Plus® (TVP‐IOP), and SW‐500® (SW‐IOP) were compared with manometric IOPs. For clinical trials, each tonometer was evaluated separately, depending on whether TVP‐IOP was higher or lower than 14 mm Hg. One‐way repeatedmeasures analysis of variance, simple linear regression analysis, and Bland‐Altman plots were used for statistical analyses. Results In ex vivo analysis, TV‐IOP and TVP‐IOP were not significantly different from manometric IOP. However, SW‐IOP underestimated IOP compared to manometry. Higher discrepancy was observed in TV‐IOP and SW‐IOP with an increase in manometric IOP. In clinical trials, no significant difference was observed between TV‐IOP (9.73 ± 2.92) and TVP‐IOP (11.36 ± 2.23) when TVP‐IOP was lower than 14 mm Hg, but SW‐IOP (8.70 ± 3.03) was significantly lower than TVP‐IOP. TV‐IOP (15.96 ± 6.47) and SW‐IOP (13.09 ± 3.72) were significantly lower than TVP‐IOP (20.08 ± 6.60) when the IOP was higher than 14 mm Hg of TVP‐IOP. Conclusions This study demonstrates that the TONOVET® and TONOVET‐Plus® provide a useful approach for ex vivo analysis. In clinical trials, results of TV‐IOP and SW‐IOP were significantly lower than of TVP‐IOP when IOP was higher than 14 mm Hg of TVP‐IOP. The characteristics of rebound tonometers should be considered in clinical settings.

“…To the authors' knowledge, no published studies on the use of Tonovet Plus ® in horses are available to date. A single study performed in rabbits states the accuracy of Tonovet ® Plus to be improved compared with Tonovet ® 16 . In addition, a recent study compared the two devices in healthy dogs and found 4.2 mm Hg higher average readings with Tonovet Plus ® than with Tonovet ® 17 .…”

Section: Introductionmentioning

confidence: 99%

Comparison of two rebound tonometers in healthy horses

Mustikka

Pietilä²,

Mykkänen

et al. 2020

Objective To obtain a reference range for evaluation of intraocular pressure (IOP) in horses using Tonovet Plus®, to compare the IOP readings obtained with Tonovet® and Tonovet Plus®, and to evaluate the repeatability of readings. Animals studied and Procedures Intraocular pressure of 30 client‐owned horses (60 eyes) with no signs of illness or ocular disease was evaluated using Tonovet® and Tonovet Plus® rebound tonometers. Horses’ mean age was 10.7 (range 6‐17) years. Triplicate measurements were performed without using sedatives or local anesthetics, with minimal restraint. Results Calculated reference intervals (the CLSI robust method) were 14.4‐27.2 mmHg for Tonovet® and 16.0‐26.1 mmHg for Tonovet Plus®. Mean values (± standard deviation, SD [± coefficient of variation, CV]) obtained with Tonovet Plus® (21.6 ± 2.45 mmHg [11.3%]) were on average 0.6 mmHg higher than with Tonovet® (21.0 ± 3.14 mmHg [15.0%]), and a negligible statistical difference between the devices was found using the paired sample t test (P = .049). The correlation coefficient for the averaged triplicate measurements was 0.73. The average CV was 4.6% and 4.4% for Tonovet® and Tonovet Plus®, respectively. Conclusions The repeatability of measurements was very good with both devices. The readings between the two devices differed statistically significantly, but the correlation was considered good and the variation was numerically small, and thus, the difference was considered clinically irrelevant. When monitoring disease process or treatment response in an individual patient, repeated readings are best performed using a similar device to avoid false interpretation of results.