Intraocular pressure measurement accuracy and repeatability of a modified Goldmann prism: Multi-center randomized clinical trial

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d616868e173">Purpose:</h5> <p id="P8">Clinically evaluate a modified surface Goldmann (GAT) tonometer prism for IOP accuracy, repeatability, and safety. </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d616868e178">Design:</h5> <p id="P9">Prospective, open-label, randomized, controlled, multicenter reference device reliability and validity analysis </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d616868e183">Methods:</h5> <p id="P10">A GAT and a modified surface GAT prism measured IOP on 173 unique eyes. The study design and analysis complied with FDA 510(k) and ANSIZ80.10–2014 guidelines. All eyes were randomized to IOP measurement by one of 5 standard prisms or 5 modified prisms, each from different manufacturing lot. Pressures were measured by 6-investigators, 2-times with each prism for a total of 1384 IOP measurements. Analysis included Bland-Altman difference accuracy, intra-operator and inter-operator IOP measurement and manufactured lot repeatability. </p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d616868e188">Results:</h5> <p id="P11">Bland-Altman indicated no IOP measurements pairs outside the +/−5mmHg guidelines. Operator and manufactured lot repeatability F-tests and one way ANOVAs indicated no statistical difference between the standard and modified prisms (all p&gt;0.10). The difference in IOP measurements of the standard and modified prisms correlated well to Dresdner CCT correction (p=0.01). </p> </div><div class="section"> <a class="named-anchor" id="S5"> <!-- named anchor --> </a> <h5 class="section-title" id="d616868e193">Conclusion:</h5> <p id="P12">A modified surface replacement prism is statistically equivalent to a flat-surfaced prism. The modified surface prism indicated statistically significant correction for CCT requiring further testing outside the ANSI standard limits (0.500mm&lt;CCT&lt;0.600mm) to examine its full potential. </p> </div>