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Aim: To assess the validity of the Tono-Pen XL as an alternative to the Goldmann applanation tonometer (GAT) for the measurement of intraocular pressure (IOP) in patients with ocular hypertension (OHT) and glaucoma. Methods: Over a 3 month period, patients with OHT or glaucoma attending a general clinic had IOP measurements taken using the Tono-Pen XL and the GAT. Tono-Pen measurements were taken by suitably trained nursing staff, while Goldmann tonometry was performed by the examining ophthalmologist. Results: There were 124 eyes of 62 patients in this study. Overall, mean IOP was 18.3 (plus or minus) 4.8 mmHg using GAT and 18.8 (plus or minus) 5.5 mmHg using the Tono-Pen. Using the Bland-Altman method, the upper and lower limits of agreement between the two devices were +10.6mmHg and -9.6 mmHg, respectively. Significant over- and under-estimates of IOP were noted in 10 (16%) patients. Conclusion: Our findings suggest that the Tono-Pen XL cannot be used as a substitute for GAT in the management of patients with glaucoma or OHT.
Z. I. Carrim. Department of Ophthalmology, St James's University Hospital, Beckett Drive, Leeds, LS9 7TF, United Kingdom. zia.carrim@doctors.org.uk
6.1.1 Devices, techniques (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)