Self-tonometry with the Ocuton S versus Goldmann tonometry

Abstract

Background: The purpose of the study was to evaluate the acceptance and reproducibility of a new self-tonometer (Ocuton S) and to compare it with the Goldmann applanation tonometer.

Methods: The Ocuton S was studied in 20 healthy volunteers and 100 patients. After detailed explanation to each individual and a number of test measurements, we studied the reproducibility and accuracy of the Ocuton S in 20 healthy volunteers with and without topical anaesthesia. Acceptance was graded by means of visual analogue scales. Each volunteer had to measure his/her own IOP in three consecutive measurements. The data were compared with Goldmann tonometry at random times. One hundred patients were introduced to the Ocuton S. Either three consecutive self-measurements of IOP were performed and then compared with three consecutive measurements by Goldmann tonometry, or vice versa. This was done randomly.

Results: Forty-one of 100 patients were unable to perform three consecutive measurements with the Ocuton S after at least 15 min introduction time to the device (non-success). Fifty-nine of 100 patients were able to measure their IOP with the Ocuton S. The mean pressure value with the Ocuton S was 23.2+/-8.2 mmHg, compared with Goldmann 18. 4+/-5.7 mmHg. The difference of 5+/-5.7 mmHg was statistically significant (paired t-test p<0.01). The visual analogue scale scores of healthy volunteers (100 mm = maximal comfort, 0 mm = not acceptable), was 72+/-31 in anaesthetised eyes and 39+/-41 mm without anaesthesia.

Conclusion: The Ocuton S seems to be an acceptable means for the majority of patients of measuring their IOP at home. Refinement of the accuracy of the device seems necessary.