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

PURPOSE: To evaluate repeatability, reproducibility, and agreement of intraocular pressure measurement with Tono-Pen using Ocufilm and polyethylene wrap tip cover in human eyes. METHODS: This is a cross-sectional, experimental study. A gas-sterilized, polyethylene wrap was used as an alternative for Tono-Pen tip cover. For the right eye, 4 measurements using polyethylene wrap tip cover were done by two examiners (A and B) in random order to assess intra-observer repeatability and inter-observer reproducibility. For the left eye, 4 measurements were done by examiner A using both polyethylene wrap tip cover and Ocufilm in random order to assess intra-observer repeatability and agreement. Bland-Altman plot and intraclass correlation coefficient (ICC) were used in all analyses. Cost minimization analysis was evaluated. RESULTS: For examiner A, the repeatability of polyethylene wrap tip cover was -0.34, 95% limits of agreement (LOA) were -3.04 to 2.36, and ICC was 0.93 in the right eyes. As for the left eyes, the repeatability of polyethylene wrap tip cover was -0.33, 95% LOA were -3.01 to 2.36, and ICC was 0.93. For examiner B, the repeatability of polyethylene wrap tip cover was -0.02, 95% LOA were -2.88 to 2.83, and ICC was 0.92. The inter-observer reproducibility of polyethylene wrap tip cover was 0.36, 95% LOA were -3.34 to 4.07, and ICC was 0.90. The repeatability of Ocufilm was -0.42, 95% LOA were -2.75 to 1.91, and ICC was 0.95. The agreement of polyethylene wrap tip cover and Ocufilm was -0.71, 95% LOA were -5.18 to 3.76, and ICC was 0.83. There were no allergic reactions or serious complications. From the cost minimization analysis, the local cost for polyethylene tip cover was approximately 8 times lower compared to Ocufilm. CONCLUSIONS: Tono-pen with Ocufilm and polyethylene wrap tip cover were used to measure the intraocular pressure. The polyethylene wrap tip cover demonstrated acceptable repeatability, reproducibility, and agreement with Ocufilm in normotensive eyes, and had a good safety profile.