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[Clinical comparison of the Tono-Pen tonometer to the Goldmann applanation tonometer]
1Dept. of Ophthalmology, the Second Xiangya Hospital of Central South University, Changsha 410011, China.
Purpose:
To compare the Tono-Pen tonometer with the Goldmann applanation and assess the precision and accuracy of the Tono-Pen tonometer.
Methods:
62 cases (111 eyes) were random measured with the Tono-Pen tonometer and the Goldmann applanation tonometer.
Results:
Overall we found that 74.8% of the Tono-Pen readings were within +/- 2 mmHg of the Goldmann applanation readings and 83.8% were within +/- 3 mmHg. The correlation coefficient between the readings of the two instruments was 0.865. The mean value of the paired differences was (-0.51 +/- 2.24)mmHg in the 9 to 30 mmHg interval.
Conclusion:
The Tono-Pen tonometer measures intraocular pressure in a manner that corresponds well to the Goldmann applanation tonometer, especially in the 9 - 30 mmHg interval. But this tonometer may overestimate the intraocular pressure in eyes with low intraocular pressure, and underestimate the intraocular pressure in eyes with high intraocular pressure.
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