Comparison of three methods of tonometry in normal subjects: Goldmann applanation tonometer, non-contact airpuff tonometer, and Tono-Pen XL

Figures & data

Figure 1 Frequency of intraocular pressure measurements (mmHg) taken with the Goldmann applanation tonometer (GAT).

Note: GAT; Haay-Streit AG, Koeniz, Switzerland.
Abbreviation: Std. dev, standard deviation.

Figure 2 Correlation analysis of intraocular pressure measurements (mmHg) taken with NCT and GAT.

Notes: The correlation is significant (R²=0.354, P<0.05). NCT; Nidek Co., Ltd., Aichi, Japan and GAT; Haay-Streit AG, Koeniz, Switzerland.
Abbreviations: GAT, Goldmann applanation tonometer; NCT, non-contract tonometer.

Figure 3 Correlation analysis of intraocular pressure measurements (mmHg) taken with the Tono-Pen^® XL and the GAT.

Notes: The correlation is significant (R²=0.328, P<0.05). Tono-Pen^® XL; Reichert Technologies, Depew, NY, USA and GAT; Haay-Streit AG, Koeniz, Switzerland.
Abbreviation: GAT, Goldmann applanation tonometer.

Figure 4 Correlation analysis of intraocular pressure measurements (mmHg) taken with the Tono-Pen^® XL and an NCT.

Notes: The correlation is significant (R²=0.240, P<0.05). Tono-Pen^® XL; Reichert Technologies, Depew, NY, USA and NCT; Nidek Co., Ltd., Aichi, Japan.
Abbreviation: NCT, non-contact tonometer.

Figure 5 Bland–Altman test for correspondence between intraocular pressure measurements (mmHg) taken with NCT and GAT.

Notes: The mean difference in intraocular pressure was 0.6 mmHg. NCT; Nidek Co., Ltd., Aichi, Japan and GAT; Haay-Streit AG, Koeniz, Switzerland.
Abbreviations: GAT, Goldmann applanation tonometer; NCT, non-contact tonometer; SD, standard deviation.

Figure 6 Bland–Altman test for correspondence between intraocular pressure measurements (mmHg) taken with the Tono-Pen^® XL and the GAT.

Notes: The mean difference in intraocular pressure was 0.7 mmHg. Tono-Pen^® XL; Reichert Technologies, Depew, NY, USA and GAT; Haay-Streit AG, Koeniz, Switzerland.
Abbreviations: GAT, Goldmann applanation tonometer; SD, standard deviation.

Figure 7 Bland–Altman test for correspondence between intraocular pressure measurements (mmHg) taken with the NCT and Tono-Pen^® XL.

Notes: The mean difference in intraocular pressure was −0.025 mmHg. Tono-Pen^® XL; Reichert Technologies, Depew, NY, USA and NCT; Nidek Co., Ltd., Aichi, Japan.
Abbreviations: NCT, non-contact tonometer; SD, standard deviation.