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Performance of the PT100 noncontact tonometer in healthy eyes.

AlMubrad TM - Clin Ophthalmol (2011)

Bottom Line: These mean differences were not statistically significant (P > 0.05, paired t-test), with the PT100 underestimating IOP measurement by 1.00 mmHg.The PT100 noncontact tonometer produced greater repeatability than the GAT in assessment of IOP, whereas GAT resulted in more reproducible results.Both techniques showed a close level of agreement on comparison, with the PT100 underestimating IOP measurement by 1.0 mmHg only, although this was not clinically or statistically significant.

View Article: PubMed Central - PubMed

Affiliation: Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia. turkim@ksu.edu.sa

ABSTRACT

Background: The purpose of this study was to assess the repeatability and reproducibility of the PT100 noncontact tonometer and to compare its consistency with the Goldmann applanation tonometer (GAT) in measuring intraocular pressure (IOP).

Methods: Triplicate IOP measurements were obtained on two separate occasions using the PT100 and GAT from randomly selected eyes in 66 healthy volunteers aged 22 ± 1 years. The repeatability and reproducibility of each techniques was assessed. Agreement between the techniques was statistically quantified using intrasession repeatability for each technique as the basis for comparison.

Results: Both techniques returned equal IOP values in the first measurement session (15 ± 3 mmHg). The second session showed a mean difference in average IOP (1 ± 0.71). The 95% limits of agreement between the techniques were -5.2 to 5.5 mmHg and -4.0 to 4.7 mmHg (sessions 1 and 2, respectively). These mean differences were not statistically significant (P > 0.05, paired t-test), with the PT100 underestimating IOP measurement by 1.00 mmHg. The mean intrasession IOP for GAT sessions 1 and 2 was 0 ± 0.90 mmHg and 0.04 ± 1.06 mmHg, respectively, and the corresponding mean IOP measurement difference for the PT100 was -0.06 ± 0.96 and -0.39 ± 0.94 mmHg (sessions 1 and 2, respectively; P > 0.05, paired t-test). Repeatability coefficients for the GAT IOP measurements were 1.8 mmHg and 2.1 mmHg for sessions 1 and 2, while the PT100 repeatability coefficient was 1.9 mmHg and 1.8 mmHg for sessions 1 and 2, respectively. The intrasession repeatability coefficient of both techniques for test-retest differences were within ±5 mmHg.

Conclusion: The PT100 noncontact tonometer produced greater repeatability than the GAT in assessment of IOP, whereas GAT resulted in more reproducible results. Both techniques showed a close level of agreement on comparison, with the PT100 underestimating IOP measurement by 1.0 mmHg only, although this was not clinically or statistically significant. Of importance is that the IOP measurements using these techniques could be interchangeable in the IOP range studied here.

No MeSH data available.


Related in: MedlinePlus

Intrasession variation of IOP with the Goldmann applanation tonometer in sessions 1 and 2. The mean difference of triplicate IOP measurements for each subject; 95% limits of agreement are depicted by the three lines.Abbreviations: IOP, intraocular pressure; SD, standard deviation.
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f1-opth-5-661: Intrasession variation of IOP with the Goldmann applanation tonometer in sessions 1 and 2. The mean difference of triplicate IOP measurements for each subject; 95% limits of agreement are depicted by the three lines.Abbreviations: IOP, intraocular pressure; SD, standard deviation.

Mentions: In assessing the reproducibility of the two techniques when measurements were taken by two different observers, the reproducibility coefficients in mean difference for both the GAT and the PT100 noncontact tonometer on a Bland–Altman plot was −0.115 mmHg, which did not vary significantly (P > 0.05, paired t-test). There was no significant correlation (P > 0.05, Pearson’s r) between the magnitude of IOP measurements within sessions for the same technique (Figures 1 and 2), between sessions for the same technique (Figure 3), and between techniques (Figure 4).


Performance of the PT100 noncontact tonometer in healthy eyes.

AlMubrad TM - Clin Ophthalmol (2011)

Intrasession variation of IOP with the Goldmann applanation tonometer in sessions 1 and 2. The mean difference of triplicate IOP measurements for each subject; 95% limits of agreement are depicted by the three lines.Abbreviations: IOP, intraocular pressure; SD, standard deviation.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104795&req=5

f1-opth-5-661: Intrasession variation of IOP with the Goldmann applanation tonometer in sessions 1 and 2. The mean difference of triplicate IOP measurements for each subject; 95% limits of agreement are depicted by the three lines.Abbreviations: IOP, intraocular pressure; SD, standard deviation.
Mentions: In assessing the reproducibility of the two techniques when measurements were taken by two different observers, the reproducibility coefficients in mean difference for both the GAT and the PT100 noncontact tonometer on a Bland–Altman plot was −0.115 mmHg, which did not vary significantly (P > 0.05, paired t-test). There was no significant correlation (P > 0.05, Pearson’s r) between the magnitude of IOP measurements within sessions for the same technique (Figures 1 and 2), between sessions for the same technique (Figure 3), and between techniques (Figure 4).

Bottom Line: These mean differences were not statistically significant (P > 0.05, paired t-test), with the PT100 underestimating IOP measurement by 1.00 mmHg.The PT100 noncontact tonometer produced greater repeatability than the GAT in assessment of IOP, whereas GAT resulted in more reproducible results.Both techniques showed a close level of agreement on comparison, with the PT100 underestimating IOP measurement by 1.0 mmHg only, although this was not clinically or statistically significant.

View Article: PubMed Central - PubMed

Affiliation: Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia. turkim@ksu.edu.sa

ABSTRACT

Background: The purpose of this study was to assess the repeatability and reproducibility of the PT100 noncontact tonometer and to compare its consistency with the Goldmann applanation tonometer (GAT) in measuring intraocular pressure (IOP).

Methods: Triplicate IOP measurements were obtained on two separate occasions using the PT100 and GAT from randomly selected eyes in 66 healthy volunteers aged 22 ± 1 years. The repeatability and reproducibility of each techniques was assessed. Agreement between the techniques was statistically quantified using intrasession repeatability for each technique as the basis for comparison.

Results: Both techniques returned equal IOP values in the first measurement session (15 ± 3 mmHg). The second session showed a mean difference in average IOP (1 ± 0.71). The 95% limits of agreement between the techniques were -5.2 to 5.5 mmHg and -4.0 to 4.7 mmHg (sessions 1 and 2, respectively). These mean differences were not statistically significant (P > 0.05, paired t-test), with the PT100 underestimating IOP measurement by 1.00 mmHg. The mean intrasession IOP for GAT sessions 1 and 2 was 0 ± 0.90 mmHg and 0.04 ± 1.06 mmHg, respectively, and the corresponding mean IOP measurement difference for the PT100 was -0.06 ± 0.96 and -0.39 ± 0.94 mmHg (sessions 1 and 2, respectively; P > 0.05, paired t-test). Repeatability coefficients for the GAT IOP measurements were 1.8 mmHg and 2.1 mmHg for sessions 1 and 2, while the PT100 repeatability coefficient was 1.9 mmHg and 1.8 mmHg for sessions 1 and 2, respectively. The intrasession repeatability coefficient of both techniques for test-retest differences were within ±5 mmHg.

Conclusion: The PT100 noncontact tonometer produced greater repeatability than the GAT in assessment of IOP, whereas GAT resulted in more reproducible results. Both techniques showed a close level of agreement on comparison, with the PT100 underestimating IOP measurement by 1.0 mmHg only, although this was not clinically or statistically significant. Of importance is that the IOP measurements using these techniques could be interchangeable in the IOP range studied here.

No MeSH data available.


Related in: MedlinePlus