The comparison of the quality score of IOP and ocular pulse amplitude (OPA) values measured by dynamic contour tonometer

Abstract

Abstract Purpose: The dynamic contour tonometer (DCT) is designed to measure the IOP independently of the corneal properties. It is foreseen of a digital LCD screen which displays the IOP, the OPA and the quality score (Q) of measurements varying from 1 (excellent) to 5 (poor). The manufacturer recommends discarding the IOP and OPA values with Q4 and 5. The aim of our study was to assess if IOP and OPA measurements with Q3 are acceptable for clinical and research purposes. Methods: 2 consecutive GAT IOP measurements were followed after 10 minutes break by 3 consecutive DCT IOP measurements in 210 patients. Only 85 patients who had IOP and OPA values with Q score 1, 2 and 3 were included in this sub‐study.The mean DCT IOP and OPA were taken for the statistical analyzes. DCT IOP Q3 was separately compared with Q2 and Q1 values. DCT IOP Q1 and Q2 were compared as well. The same comparison was performed for OPA. The Pearson correlation was used for correlation assessment. Results: The mean age was 56±14 years. The mean IOP with GAT was 18.2±4.4 mmHg. The mean IOP Q3, Q2 and Q1 were respectively 17.8±3.3, 17.5±3.3 and 17.5±3.4 mmHg. The mean OPA Q3, Q2 and Q1 were respectively 2.5±1.0, 2.5±1.0 and 2.5±0.9 mmHg.The Pearson correlation for DCT IOP Q3‐2, DCT IOP Q3‐1 and DCT IOP Q2‐1 were equal to 0.9 (r= 0.28, p<0.01).The Pearson correlation for OPA Q3‐2 was: 0.8, for OPA Q3‐1: 0.7 and for OPA Q2‐1: 0.8. The difference between these value were not statistically significant. Conclusions: The IOP and the OPA values with Q 1, 2 or 3 measured by DCT are not significantly different and can be taken into account for clinical and research purposes.