Comparison of Perkins, Tono-Pen and Schiotz tonometers in paediatric patients under general anaesthesia

ABSTRACT

This cross-sectional study aimed to investigate if the Tono-Pen, Schiotz and Perkins tonometers could be used interchangeably in general practice for measuring elevated intraocular pressure. A total of 74 eyes of 37 paediatric patients under general anaesthesia were checked with all 3 tonometers. All of the tonometers gave significantly different measurements from each other. However, with a mean difference of 1.4 mmHg and 95% limits of agreement of -5.7 to +8.6, the greatest agreement was between the Perkins and Tono-Pen tonometers. The Perkins tonometer is a hand-held variant of the Goldmann tonometer [the gold standard for intraocular pressure measures]. Therefore the Tono-Pen with its ease of use and safety could be a reliable device for use in general practice