Transpalpebral tonometry: reliability and comparison with Goldmann applanation tonometry and palpation in healthy volunteers

Abstract

Background/aim: TGDc-01 is a new, portable, transpalpebral tonometry device. The aim of this study was to evaluate the reproducibility of this method, including intraobserver and interobserver deviations, and to compare the results with those of Goldmann applanation tonometry and palpation of intraocular pressure (IOP). Methods: A total of 40 eyes of 20 healthy volunteers were included. Two independent parallel observers (1 and 2) performed three replicate measurements per eye, respectively, both using TGDc01 tonometry, one observer (3) performed three replicate measurements using Goldmann applanation tonometry, and one observer (4) measured the IOP via palpation. Intraindividual deviations within and between both observers using TGDc-01 tonometry and between all three methods were investigated about clinically relevance by comparison of medians and quartiles, statistically significance by pairwise sign tests. Comparisons between observers and methods were based on averaged IOP values of the three individual measurements for each observer and each patient. Intraobserver deviations were analysed by means of Friedman tests. Results: Observers 1 and 2 showed a statistically significant intraobserver deviation when using TGCc-01 (Friedman p = 0.007 for observer 1 and p = 0.002 for observer 2). There was no statistically significant interobserver deviation between observers 1 and 2 (sign test p = 0.200); however, in 45% of the eyes interobserver deviations were larger than plus or minus 3 mm Hg. The median intraindividual deviation between TGDc-01 and Goldmann (TGDc-01 minus Goldmann) was 0 mm Hg (interquartile range 21; 2 mm Hg; sign test p = 0.522); but deviations were larger than plus or minus 3 mm Hg for 38% of the 40 eyes. Median intraindividual deviation between TGDc-01 and palpation (TGDc-01 minus palpation) was 22 mm Hg (interquartile range 24; 1 mm Hg; sign test p = 0.018), but deviations were larger than plus or minus 3 mmHg for 43% of eyes. Median intraindividual deviation between Goldmann and palpation (palpation minus Goldmann) was 2 mm Hg (interquartile range 22; 4 mm Hg; p = 0.429), but deviations were larger than plus or minus 3 mm Hg in 48% of the eyes. Conclusion: Interobserver deviations using TGDc-01 tonometry and intraindividual deviations between TGDc-01 tonometry, Goldmann applanation tonometry, and palpation of IOP were found to be clinically relevant. Thus, according to our results TGDc-01 could not be established as a substitute or diagnostic alternative method for Goldmann applanation tonometry. But as deviations between TGDc01 and Goldmann turned out smaller than between palpation of IOP and Goldmann, TGDc-01 seems to provide a better choice for tonometry in patients, in whom Goldmann applanation tonometry is not possible.

Diaton tonometry: an assessment of validity and preference against Goldmann tonometry

“…Other smaller comparison studies, by Troost et al and García Resúa et al have also not shown encouraging results for the TGDc-01. 6,7 It is interesting that, despite being considered an improved version of the TGDc-01, the Diaton does not appear to offer better agreement with GAT.…”

Surveillance for ocular hypertension: an evidence synthesis and economic evaluation

“…In total, 10 studies 124,127,137,138,168,176,178,191,198,208 (50%) reported individual measures taken within 1 hour. In 12 studies (60%) the same clinical data were available for interpretation as would be available in clinical practice 124,127,133,137,138,158,162,168,172,177,205,207 and it was reported that the examiner(s) were masked to the results. 124,125,158,162,168,172,[176][177][178]205,207,208 In seven studies 125,127,172,177,178,205,208 (35%) the tonometers used were calibrated.…”

“…Fourteen studies provided data on participants' race. Almost all studies reported the diagnosis; populations varied: healthy volunteers, 158 those diagnosed with OHT 155 or glaucoma 196 or a mixed population.…”

“…Twenty studies 124,125,127,133,[136][137][138]158,162,164,168,172,[176][177][178]191,198,205,207,208 enrolling 1509 participants (2091 eyes) compared transpalpebral tonometer with GAT. Figure 45 summarises the quality assessment for these studies.…”

Tonometry: an overview

“…Non-corneal and trans-palpebral tonometry does not involves contact with the cornea and does not require topical anesthetic during routine use. The tonometer is not a substitute or alternative for Goldmann tonometry but may be helpful as a screening tool [18,19]. It is independent of corneal biomechanics such as corneal thickness, other biometric properties and intra-ocular pressure can be obtained in patients wearing contact lenses.…”