OBJECTIVE: To study if the Tono-Pen, a hand held digital tonometer, can replace Schiøtz tonometry in general practice. DESIGN: Tonometry with Tono-Pen and Schiøtz tonometer were compared. SETTING: Group practice with two general practitioners (GPs). PATIENTS: 48 consecutive patients over 40 years of age. MAIN OUTCOME MEASURES: The mean difference between intra ocular pressure (IOP) measured with the two methods with 95% confidence intervals and 95% limits of agreement between them. RESULTS: One observer found a mean difference between methods of 0.3 mmHg and 95% limits of agreement of +/- 4 mmHg. The other observer with a different Schiøtz tonometer, had a mean difference of approximately -2 mmHg and 95% limits of agreement from -8 to +4 mmHg. CONCLUSION: We consider the Tono-Pen to be an alternative to Schiøtz tonometry. The maximum mean difference between the methods for one GP, 1.9 mmHg, was within clinically acceptable limits. Possible reasons for the different agreement for the two observers are discussed.
OBJECTIVE: To study if the Tono-Pen, a hand held digital tonometer, can replace Schiøtz tonometry in general practice. DESIGN: Tonometry with Tono-Pen and Schiøtz tonometer were compared. SETTING: Group practice with two general practitioners (GPs). PATIENTS: 48 consecutive patients over 40 years of age. MAIN OUTCOME MEASURES: The mean difference between intra ocular pressure (IOP) measured with the two methods with 95% confidence intervals and 95% limits of agreement between them. RESULTS: One observer found a mean difference between methods of 0.3 mmHg and 95% limits of agreement of +/- 4 mmHg. The other observer with a different Schiøtz tonometer, had a mean difference of approximately -2 mmHg and 95% limits of agreement from -8 to +4 mmHg. CONCLUSION: We consider the Tono-Pen to be an alternative to Schiøtz tonometry. The maximum mean difference between the methods for one GP, 1.9 mmHg, was within clinically acceptable limits. Possible reasons for the different agreement for the two observers are discussed.