Repeatability, reproducibility, agreement, and safety of tono-pen tip cover for intraocular measurement using latex and polyethylene wrap

Abstract

Background: Tono-Pen® is a regularly used device. A tip cover is needed to prevent damage to the transducer tip and patient-to-patient contamination. Ocufilm® (OF), latex disposable tip cover, is costly and able to cause allergic reactions. Objective: To evaluate repeatability, reproducibility, and agreement of intraocular pressure measurement with Tono-Pen® using OF and polyethylene wrap tip cover (PE) in human eyes. Materials and Methods: This is a cross-sectional, experimental study. For the right eyes, 4 measurements using PE were done by two raters (A and B) in random order to assess intra-rater repeatability and inter-rater reproducibility. For left eyes, 4 measurements were done by rater A using both PE and OF in random order to assess intra-rater repeatability and agreement. Results: A total of 128 participants were recruited. The mean difference in mmHg (95% limits of agreement, intraclass correlation coefficient) was -0.34 (-3.04 to 2.36, 0.93) for repeatability of PE by rater A in the right eyes, -0.33 (-3.01 to 2.36, 0.93) for repeatability of PE by rater A in the left eyes, -0.02 (-2.88 to 2.83, 0.92) for repeatability of PE by rater B, 0.36 (-3.34 to 4.07, 0.90) for inter-rater reproducibility of PE, -0.42 (-2.75 to 1.91, 0.95) for repeatability of OF by rater A, and -0.71 (-5.18 to 3.76, 0.83) for agreement between both tip covers. The only complication was punctate epithelial erosion. No sight-threatening complications and allergic reactions were found. Cost minimization analysis found that PE had approximately 8-time decreased cost compare to OF. Conclusions: For intraocular pressure measurement with Tono-Pen, PE demonstrated acceptable repeatability, reproducibility, and agreement with OF with a good safety profile.