Goldmann tonometer error correcting prism: clinical evaluation

Figures & data

Figure 1 CATS versus GAT tonometer prism applanating surface.

Abbreviations: CATS, correcting applanation tonometry surface; GAT, Goldmann applanation tonometry.

Figure 2 Photograph of the CATS tonometer prism applanating surface.

Abbreviation: CATS, correcting applanation tonometry surface.

Figure 3 CATS minus GAT IOP difference correlated to CCT.

Abbreviations: CATS, correcting applanation tonometry surface; CCT, central corneal thickness; GAT, Goldmann applanation tonometry; IOP, intraocular pressure.

Figure 4 CATS minus GAT IOP difference correlated to CRF.

Abbreviations: CATS, correcting applanation tonometry surface; CRF, corneal resistance factor; GAT, Goldmann applanation tonometry; IOP, intraocular pressure.

Figure 5 CATS minus GAT, IOP difference correlated to corneal curvature.

Abbreviations: CATS, correcting applanation tonometry surface; GAT, Goldmann applanation tonometry; IOP, intraocular pressure.

Figure 6 CATS versus GAT, IOP correlation.

Abbreviations: CATS, correcting applanation tonometry surface; GAT, Goldmann applanation tonometry; IOP, intraocular pressure.

Table 1 CATS versus GAT statistical analysis

Parameter	GAT correction slope	Correlation coefficient	Multiple regression P-value	Measurement variance
Corneal thickness	−0.024 mmHg/µCCT	0.43	0.02	–
Corneal curvature	−0.06 mmHg/Diopter	0.20	0.19	–
Corneal resistance	−0.39 mmHg/CRF unit	0.27	0.2	–
Combined multiple regression	–	0.43	F<0.01	–
CATS repeatability	Mean IOP =17.5 mmHg	–	–	0.27
GAT repeatability	Mean IOP =17.8 mmHg	–	–	0.19

Abbreviations: CATS, correcting applanation tonometry surface; GAT, Goldmann applanation tonometry; IOP, intraocular pressure.

Figure 7 Bland–Altman analysis CATS versus GAT.

Abbreviations: CATS, correcting applanation tonometry surface; GAT, Goldmann applanation tonometry; IOP, intraocular pressure; SD, standard deviation.