New-generation portable tonometers: comparison of the Keta and Goldmann tonometers

The Keta Smart-001 is a recently introduced portable battery-operated tonometer with a digital readout. To determine the reliability of the Keta tonometer, intraocular pressure (IOP) measurements were taken in a masked fashion with the Keta tonometer and the Goldmann tonometer in both eyes of 60 patients (20 with and 40 without glaucoma) recruited from general ophthalmology and glaucoma clinics. The results were analysed with an F-test analysis of variance. The Keta tonometer significantly underread the IOP and was totally unreliable in patients with glaucoma. Our results indicate that Keta tonometry should not be used for the screening and management of glaucoma.