Background: Glaucoma is a disease with progressive and irreversible optic neuropathy, and a leading cause of blindness worldwide. Complications of glaucoma can be delayed or prevented. General practitioners (GPs) should measure intra ocular pressure (IOP) in patients with symptoms of or risk factors for acute or chronic elevated IOP. There are several portable tonometers commercially available. Objective: Compare the use of three portable tonometers by an inexperienced tonometrist, concerning IOP readings, time consumption and patient comfort.Material: 20 volunteers with no past ocular pathology with a mean age of 27 years (range 21–37 years). Method: IOP was measured in both eyes by a medical student with Schiotz’ tonometer, TonoPen and ICare, and compared with a gold standard; IOP readings with Goldmann’s applanation tonometer by an experienced tonometrist. Time consumption and patient comfort were recorded and compared regarding local anaesthesia and the three portable tonometers. Results: Mean IOP readings in the right and left eye were 13,5 ± 1,9 mmHg (range 10-18) and 13,6 ± 1,8 mmHg (range 10-18), 15,9 mmHg ± 3,2 (range 11-22) and 14,9 ± 2,3 mmHg (range 11-19), 14,5 ± 2,4 mmHg (range 10-20) and 14,1 ± 2,5 mmHg (range 11-19), 10,7 ± 3,0 mmHg (range 6,5-15,9) and 11,1 ± 2,8 mmHg (range 7,1-17,3), for Goldmann, ICare, TonoPen and Schiotz’, respectively. IOP readings of the three portable tonometers differed significantly (p=0,05) from those of Goldmanns applanation tonometer, apart from TonoPen’s of IOP in the left eye. The application of local anaesthesia yielded the highest reported level of patient discomfort. The reported levels of discomfort from IOP readings were highest after use of Schiotz’, then TonoPen and ICare, in decreasing succession. Mean time consumption for IOP readings were 68,6 ± 22,9 sec (range 44-129), 84,3 ± 41,3 sec (range 55-244) and 131,4 ± 61,3 sec (range 74-299) for ICare, TonoPen and Schiotz’, respectively. Conclusion: The accuracy of Schiotz’, ICare and TonoPen is acceptable for screening purposes. Shiotz’, however, shows lower IOP values than the gold standard. In this study, TonoPen was the most userfriendly of the three. Not requiring local anaesthesia gives ICare an advantage in measuring IOP, especially in children.