[Comparison of precision of the TonoPenXL with the Goldmann and Draeger applanation tonometer in a sitting and recumbent position of the patients -- a clinical study on 251 eyes]

Abstract

Purpose: Comparison of precise intraocular pressure (IOP) measurement with TonoPenXL, Goldmann and Draeger applanation tonometer in a sitting and recumbent position.

Material and methods: The IOP of 251 eyes of 127 consecutive patients (SFB 539) was measured prospectively in a sitting position (1 x Goldmann, 3 x TonoPenXL) and in recumbent position (1 x Draeger, 3 x TonoPen). The mean of three TonoPenXL measurements was only accepted in a 5 % interval. Additionally, corneal ultrasonic pachymetry (Tomey, AL-2000), central corneal power, refractive error, gender and age were registered.

Results: The IOP measured with the TonoPenXL was in 92 % in a range of 2 mm Hg from the Goldmann standard. In a vertical position, the IOP TonoPenXL (16.7 +/- 4.5 mm Hg) was 0.2 mm Hg lower than the IOP Goldmann (16.9 +/- 5.1 mm Hg; regression analysis: IOP TonoPenXL = 1.78 + 0.88 IOP Goldmann). In a horizontal position, the IOP TonoPenXL (17.5 +/- 5.0 mm Hg) was 0.5 mm Hg higher as the IOP Draeger (17.0 +/- 5.3 mm Hg; regression analysis: IOP TonoPen = 0.34 + 1.016 IOP Draeger). Using the TonoPenXL, the IOP was 0.8 mm Hg higher in recumbent position than in a sitting position (regression analysis: IOP TonoPen recumbent position = - 2.27 + 1.19 IOP TonoPen sitting position). We found no relationship found between central corneal power, central corneal thickness and IOD measured with the TonoPenXL.

Conclusions: The TonoPenXL is useful for IOP measurement in a sitting and recumbent position. The results are reproducible in 92% with the Goldmann-applanation tonometer. The ophthalmologist has a comfortable measurement and screening tool for consultations or IOP investigation under general anaesthesia.