Comparison of the accommodative amplitude measured with and without the use of a specialised accommodative rule in children.

Objective: To determine the agreement between measurements of accommodative amplitude (AoA) in children using a specialised accommodative rule and measurments without it.

Methods: A total of 502 children underwent optometric examinations, including the measurement of visual acuity, objective and subjective refraction. AoA measurements were done with and without the Berens accommodative rule. The measurements of AoA were conducted monocularly using a -4 D lens. A fixation stick containing English letters equivalent to 20/30 visual acuity and a long millimetre ruler was used to measure AoA without the accommodative rule. This measurement was performed by the two trained examiners. The agreement between these methods was reported by 95% limits of agreement (LoA) and interclass correlation coefficient (ICC).

Results: The mean age of the participants was 11.7±1.3 years (range: 9-15 years) and 52.4% were male. The mean AoA with and without the accommodative rule was 20.02±6.02 D and 22.46±6.32 D, respectively. The 95% LoA between the two methods was -12.5 to 7.5 D, and the ICC was 0.67 (95% CI 0.63 to 0.70). The 95% LoA was narrower in higher age groups and males compared with females (18.92 vs 20.87). The 95% LoA was narrower in hyperopes (16.83 D) compared with emmetropes (18.37 D) and myopes (18.27 D). The agreement was not constant and decreased in higher values of AoA.

Conclusion: There is a poor and non-constant agreement between the measurements of the AoA with and without the accommodative rule. The mean AoA was 2.5 D lower with using the accommodative rule.