Objective: To compare the effect of using the fingertip of a surgical glove over Ocufilm® (Reichert Technologies, NY, USA) on the agreement and reproducibility of measuring intra-ocular pressure (IOP) by the Tono-Pen® XL (Reichert Technologies, NY, USA).
Study design: Experimental, clinical study.
Material and Method: Patients were randomized into two groups to receive IOP measurements using Tono-Pen® XL with two different types of tip covers. In Group 1, the IOP of the right eyes were first measured using Ocufilm® as the tip cover, followed by using the fingertip of a surgical glove. As for the left eyes, the tip of the surgical glove was used first, followed by use of Ocufilm®. In Group 2, the IOP of the right eyes was first measured using the tip of the surgical glove, followed by use of Ocufilm®, while for the left eye the latter was used first, followed by the tip of the surgical glove. A single operator measured the IOP in each eye twice using each type of tip cover. Agreement between the Tono-Pen® XL measurements using the two different tip covers was analyzed using the Bland Altman analysis. The difference between the repeated measures was assessed for reproducibility of the Tono-Pen® XL measurements with regard to each type of tip covers.
Results: 100 patients (200 eyes) were recruited into the present study. The mean difference of IOP taken by the Tono-Pen® XL covered with Ocufilm® and the fingertip of a surgical glove was -0.21 mmHg (95%CI: -0.36 to -0.05). The limits of agreement (confidence interval 95%) as calculated by the Bland-Altman plots for Ocufilm-Fingertip of a surgical glove was -2.43 to +2.02 mmHg. The coefficient of repeatability of the Ocufilm® vs. the surgical glove was nearly the same (1.74 vs. 2.37, respectively).
Conclusion: A significant agreement exists between using Ocufilm® and the fingertip of a surgical glove to cover the tip of a Tono-Pen® XL for measuring IOP. The coefficient of repeatability was comparable between the two different types of tip covers. When measuring IOP, the tip of a Tono-Pen® XL could therefore be covered by either Ocufilm® or the fingertip of a surgical glove without compromising accuracy.

Keywords: Intra-ocular pressure, IOL, Tono-Pen® XL, Ocufilm®, Surgical glove, Agreement, Reproducibility