Abstract

P 121

Ballistic transpalpebral tonometry: Clinical experience in glaucoma patients

Mario Matthaei, Stephan Linke, Toam Katz
Augenklinik, Universitätsklinikum Hamburg-Eppendorf, Hamburg

Objective
The ballistic transpalpebral tonometer (BTT) (Diaton, Bicom inc.) is a newly developed, portable device measuring intraocular pressure (IOP) without direct eyeball contact. It is potentially superior to the Goldmann applanation tonometer (GAT) by eliminating the need for topical anaesthesia and Fluorescein drop, and avoiding contact with cornea and sclera. We report our clinical experience with this new method since there are only few reports found in literature.
Methods
The IOPs of 101 eyes of 53 randomly selected glaucoma patients presenting to our clinic were measured initially by GAT. Twenty minutes later BTT tonometry was performed on the same patient by another masked investigator. The results of both methods were compared using paired t-test with significance level of p<0.05.
Results
The median IOP measured by GAT was 13 mmHg (Interquartile range (IQR) 10-16 mmHg) and using BTT 10 mmHg (IQR 8-12 mmHg). The mean IOP measured by GAT was 14,1 ± 6,2 SD mmHg and by BTT 10,3 ± 3,4 SD mmHg. Thus, BTT tends to generate lower IOP values. This result was statistically significant (p<0,001).
Conclusions
GAT is widely used in measuring IOP. Modern devices like air puff tonometer, tonopen and BTT have emerged to improve compliance, safety and ease of use. BTT is a portable device comfortable to handle and requires no direct eyeball contact. Our study shows in line with previous studies on transpalpebral tonometry that the new BTT delivers significantly lower IOPs in Glaucoma patients compared to GAT, particularly in high IOPs. This effect has to be considered and needs further evaluation.

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