Repeatability and reproducibility of applanation resonance tonometry: a cross-sectional study

Abstract

BackgroundTo assess repeatability (intra-observer variability) and reproducibility (inter-operator variability) of intraocular pressure (IOP) measurements with servo-controlled Bioresonator Applanation Resonance Tonometry (ART) and to evaluate possible influential factors.MethodsThe study included 178 patients (115 glaucoma and 63 controls; one eye per subject). IOP was measured once with a Goldmann applanation tonometer (GAT) and twice by ART (ART1, ART2), in randomized sequence, by a single operator to assess intra-operator variability. Each ART measurement consisted on 3 readings. To assess inter-operator variability 2 evaluators performed 2 measurements each (in random order) on the same patient. Repeatability and reproducibility were assessed by the coefficient of variation (CoV) and intraclass correlation coefficient (ICC).ResultsIn the entire cohort, ART1 was 0.4 ± 2.2 mmHg (−7.0 to 5.7 mmHg) higher than ART2 (p = 0.03) regardless of test order. Intra-operator CoV was 7.0% ± 6.3%, and ICC was 0.80-0.92. Inter-operator CoV ranged between 5.7% ± 6.1% and 8.2% ± 7.2%, and ICC between 0.86 and 0.97. ART1 and 2 were respectively 1.7 ± 3.1 and 1.3 ± 3.1 mmHg higher than GAT (p < 0.01). Test-retest difference with ART fell within ±1 mmHg in 41% of cases, within ±2 mmHg in 70%, within ±3 mmHg in 85%. 15% had a test-retest difference higher than ± 3 mmHg; Bland-Altman 95% intervals of confidence were −3.9 and +4.6 mmHg. Results were unaffected by age, diagnosis, central corneal thickness, keratometry, operator, randomization sequence.ConclusionsIn most cases ART repeatability and reproducibility were high, with no differences due to patients’ characteristics. ART measurements overestimated GAT by a mean of 1.3-1.7 mmHg.

A comparison of NCT, Goldman application tonometry values with and without fluorescein

“… 8 The ideal device must be easy to use, fast, safe, and precise, irrespective of patient posture or age, cooperation by the patient, and variability due to examiners. 9 , 10 …”

Aktueller Stellenwert der Druckmessung: Messverfahren und Fehlerquellen

“…Das Ziel der Entwicklung ist eine größere Untersucherunabhängigkeit und eine geringere Abhängigkeit von kornealen Parametern. Bei noch sehr wenig publizierten klinischen Daten konnte gezeigt werden, dass die Methode wegen Abweichungen bei einem IOD > 23 mmHg nicht direkt mit der Goldmann-Applanationstonometrie vergleichbar ist [29]. Eine Überlegenheit gegenüber der Goldmann-Applanationstonometrie in puncto Messwiederholungsgenauigkeit konnte bisher noch nicht belegt werden [30].…”

A comparison of intraocular pressure values obtained using a Goldmann applanation tonometer and a handheld version of applanation resonance tonometer: A preliminary report

“…The ART results were repeatable but the 2 nd (ART 2) was lower than the 1 st (ART 1), probably due to the increased tranquility of the patients during the 2 nd test. 8,12 Also, Salvetat et al investigated the repeatability and accuracy of servo-controlled ART. They obtained high repeatability of ART, but significantly lower than GAT.…”

“…Common conclusion was drawn -ART overestimated GAT values, especially in patients with high IOP. 8,13 Many papers compare new techniques of IOP measurement usually with a Goldmann tonometer as a reference point. Jóhannesson et al in a prospective study of 53 subjects compared 3 tonometry methods -GAT, Pascal dynamic contour tonometry (DCT), and ART.…”