Are traditional methods of balancing accommodation still useful in the modern optometry office? A comparison of methods

The goal of this research is to compare the usefulness of both Turville infinity balance (TIB) and Humphriss immediate contrast (HIC) as methods of balancing accommodation. Statistical analysis of test results and practical application of both tests were taken into account. A group of 50 people between 18 to 72 years of age were examined. Balancing the state of accommodation of each eye by the two aforementioned methods was performed after refractive examination and full correction of refractive errors. The examination was carried out by the use of phoropter and optotypes on the LCD monitor. Bland–Altman plots were used as a method of statistical analysis. Calculations were made by the use of the programs Excel 2000 and MedCalc. Three variables d, T and H were defined as the differences in spherical lens powers, right and left eye respectively, after monocular refraction (d ), after the balance of accommodation by the TIB test (T ) and after the balance of accommodation by HIC test (H ). The mean difference between TIB and HIC methods for the same individuals was +0.05 (95% limits of agreement: from –0.40 to +0.51 D), the mean difference between the refraction monocular (d ) and the TIB method (T ) was +0.01 D (95% limits of agreement: –0.48 to +0.50 D), the mean difference between monocular refraction (d ) and HIC method (H ) was 0.07 D (95% limits of agreement: from –0.56 to +0.69 D). Comparison of the selected methods of balancing accommodation shows that for patients, in whom it can be used, the Turville infinity balance test is a superior method to the Humphriss immediate contrast test