Abstract
Purpose:
To evaluate the accuracy of intraocular pressure (IOP) measurements of the newly available iCare HOME (RT-HOME) rebound tonometer compared to the iCare ONE (RT-ONE) rebound tonometer and Goldmann applanation tonometry (GAT).
Methods:
In case of sixty-four patients (mean age 57.66 ± 19.48 years) IOP measurements were obtained with each of the above-mentioned tonometers by an ophthalmologist (o). In addition, patients (p) measured their own IOP with the RT-HOME and the RT-ONE. The means and standard deviation for all tonometers were compared. Agreement between the tonometers was calculated using Bland-Altman plots.
Results:
Mean IOP's obtained were 15.23 ± 6.42 mmHg (RT-ONE(o)), 15.07 ± 6.68 mmHg (RT-ONE(p)), 14.36 ± 6.24 mmHg (RT-HOME(o)), 14.48 ± 6.08 mmHg (RT-HOME(p)) and 15.31 ± 4.40 mmHg (GAT). Bland-Altman analysis revealed a mean difference (bias) between RT-HOME(o) and RT-ONE(o), between RT-HOME(o) and RT-HOME(p), and between RT-HOME(o) and GAT of -0.87, -0.21, and -0.95 mmHg, respectively, with 95%-limits of agreement of -5.01 to 3.26, -5.39 to 4.97, and -7.58 to 5.68 mmHg, respectively. Linear regression of the Bland Altmann Analysis at RT-HOME(o) vs. GAT revealed a proportional error over the range of pressures: slope = 0.37, p < 0.001.
Conclusions:
The measurement of both RT-HOME and RT-ONE revealed in general a high congruency with the GAT. The highest consistency of IOP measurements between (o) and (p) refers to RT-HOME. Both rebound tomometers, in particular the RT-HOME, indicated in average lower IOP values than those taken with the applanation tonometry. RT-HOME seems to overestimate IOP in higher IOP values and underestimate IOP in lower IOP range.