A Comparative Study Between the Goldmann Applanation Tonometer and the Non-Contact Air-Puff Tonometer (Huvitz HNT 7000) in Normal Eyes

OBJECTIVE: To assess whether the non-contact air-puff tonometer (NCT) is an appropriate alternative to the Goldmann applanation tonometer (GAT) for measuring intraocular pressure (IOP). PATIENTS AND METHODS: An observational, cross-sectional, and comparative study with a quantitative approach was carried out. Two techniques for IOP measurements using the standard GAT and the NCT were compared. A total of 180 eyes from 90 patients were included in the study. RESULTS: The total mean IOP according to NCT measurements was 14.12 mmHg, and the total mean IOP according to the GAT was 12.98 mmHg; these values were significantly different (p=0.0018). When dividing the participants into three groups according to the measurement range obtained and comparing the mean NCT and GAT measurements in each group, in Group 1 (10–15 mmHg), no statistically significant difference was found between the means of the two tonometers (p=0.3100), a difference was observed between Group 2 (16–19 mmHg) and Group 3 (20 mmHg or more) (p<0.001). When dividing the participants by age group, the means obtained by the two tonometers also differed significantly between Group 4 (40–59 years) and Group 5 (60 years or more) (p<0.0001). In all groups, the mean measurements by the NCT were higher than those by the GAT. CONCLUSION: The NCT presented an approximate mean of the measures with the GAT in group 1 but was overestimated in the measurements of the groups 2 and 3.