[Is There Really Agreement between Rebound and Goldmann Applanation Tonometry Methods? Results of a Systematic Review...

After its introduction in 2003 the iCare® rebound tonometry has gained wide acceptance, mostly as a result of immediate method comparison trials showing high concordance with the Goldmann applanation tonometry (GAT) as a reference method. The objective of this systemic review was the synopsis of the current literature as a rationale of a concordance evaluation between the iCare® rebound and the Goldmann applanation tonometry methods.

The PubMed database was searched for Anglo-American and German publications comparing intraindividually the two tonometry methods and having been published during the period 01/2005 to 08/2014. The primary endpoint of the review was the reported IOD deviation [mmHg] between the two devices; for each trial, this primary endpoint was parameterised in terms of the "mean deviation" as well as the "relative frequency [%] of measurements with an intraindividual deviation of ≥ ± 3 mmHg". A total of 33 published method comparison studies concerning the iCare TA01i device were included, 17 of them being published between 01/2009 and 08/2014. The number of analysed eyes ranged between 28 and 445; 17 of the 33 studies reported more than 100 examined eyes. 7 of the 33 studies included only healthy eyes.

Only 10 out of the 33 studies reported a mean deviation of more than ± 1.5 mmHg, 7 of these were published between 01/2009 and 08/2014. Only 12 of the 33 studies reported the relative frequency of intraindividual deviations ≥ ± 3 mmHg, 7 of them reporting a frequency > 20 % (with a maximum of 51 %), with higher frequencies being derived from samples showing higher IOD levels according to the GAT reference.

As concluded from the current literature the iCare® rebound and the Goldmann applanation tonometry methods cannot be considered exchangable.