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Custom-Made Polyethylene Tono-Pen Tip Cover for Intraocular Pressure Measurement: Evaluation in a Controlled Eye
Pukkapol Suvannachart1,2, Somkiat Asawaphureekorn1,2, Phornrak Sriphon1
1Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Objective:
To evaluate the repeatability, reproducibility, agreement, and safety of intraocular pressure (IOP) measurements using a Tono-Pen with a polyethylene tip cover (PC) compared to the latex tip cover (LC).
Animal Studied:
A controlled eye model and healthy canine eyes.
Procedures:
Measurements were performed in two phases. In the eye model, 55 intra-balloon pressure levels (10 to 30 mmHg) were tested. Two measurements for each tip cover were performed to assess repeatability and agreement between the LC and PC. In canine eyes, repeatability and reproducibility of the PC were assessed using measurements from two examiners (77 eyes), while agreement between PC and LC was assessed using measurements by one examiner (79 eyes). Statistical analyses included mean differences (MD) and 95% limits of agreement (LOA) using the Bland-Altman method, and intraclass correlation coefficients (ICC).
Results:
In the eye model, MD, LOA, and ICC were 0.02, -4.40 to 4.44, and 0.79 for PC repeatability; -0.25, -4.55 to 4.05, and 0.78 for LC repeatability; 0.56, -5.23 to 6.36, and 0.63 for LC and PC agreement. In canine eyes, MD, LOA, and ICC were -0.08, -4.61 to 4.47, and 0.84 for PC repeatability; -0.14, -5.44 to 5.16, and 0.77 for PC reproducibility; 0.13, -3.87 to 4.13, and 0.84 for LC and PC agreement. No corneal complications were observed in any measurements.
Conclusions:
Compared to the conventional LC, the custom-made PC proved to be a safe and reliable alternative tip cover for IOP measurement, demonstrating good repeatability, reproducibility, and agreement.
