Accuracy of the Tonosafe disposable tonometer head compared to the Goldmann tonometer alone.
OBJECTIVE
To assess the accuracy of the Tonosafe disposable prism tonometer head via a randomised controlled prospective trial.


METHODS
The intraocular pressure (IOP) of 69 patients (31 men, 38 women) involving 137 eyes was measured using both the Tonosafe disposable and the Goldmann tono-meter head. The average age of patients was 66.5 years (range 23-93 years). The two examiners (PM and SL) who performed tonometry were masked while a separate observer read the IOP measurements. The order was randomised between Tonosafe and Goldmann devices. The minimum interval between the two measurements was 15 min. Patients with corneal and external diseases were excluded from the study.


RESULTS
The mean IOP using the Goldmann tonometer head was 17.44 +/- 4.97 mmHg. The mean IOP using the Tonosafe disposable head was 17.58 +/- 5.03 mmHg. The mean difference was 0.14 +/- 1.73 mmHg (95% CI -0.44, 0.16, P= 0.36). Subgroup analysis on eyes with IOP > 21 mmHg showed the Tonosafe disposable head was on average 0.15 +/- 2.40 mmHg higher than the Goldmann tonometer head. There was a high level of correlation between the IOPs obtained with the Goldmann and Tonosafe heads. Pearson's coefficient of correlation was 0.94 (P < 0.0001).


CONCLUSIONS
The Tonosafe disposable prism head was found to be accurate in IOP measurement, even in the higher range.
Department of Ophthalmology, Liverpool Hospital, Sydney, New South Wales, Australia.
Peter
P
Kim
Somsak
S
Lertsumitkul
Meaghan
M
Clark
Leeanne
L
Gardner
Peter
P
Macken
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004209:Disposable Equipment / Q000592:standards; D005260:Female; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014065:Tonometry, Ocular / Q000592:standards*