Factors Affecting Reliability of Humphrey Visual Field Testing
Purpose
To determine factors influencing Humphrey Visual Field (HVF) reliability in patients performing the test for the first time.
Methods
Prospective case-control study. 1775 consecutive patients undergoing HVF testing for the first time were included. A test was reliable if false positives <33%, false negatives <33% and fixation loses <20%. Patients who performed the test reliably were compared to those who did not. Differences in demographics, payment class, and test administrators were analysed using t-test, chi-squared test and multi-nominal logistic regression analysis where appropriate.
Results
The mean age of 1775 patients was 56.3±16.1 years; 54% were female, 78% were Chinese, and 59% were receivng fee subsidies. 63.2% and 24.6% of patients performed the test reliably on the first and second attempts respectively; 12.2% could not perform a reliable test after 2 attempts. Patients who performed the test reliably on the first attempt were signifcantly younger than those who did not (53.9±15.7 vs 60.3±16.1, p<.001). On regression analysis, difference in test administrator also had a significant effect on reliable test performance (p<.001). Gender, race and payment class had no effect on test reliability.
Conclusion
Test administrators and older age were significantly associated with poor reliability amongst patients performing the HVF test for the first time. These factors should be addressed to improve the reliability in these patients.