Investigation of amplitude of accommodation among Ghanaian school children

Background: Deficient amplitude of accommodation is the most frequently used criteria in an optometric practice in diagnosing whether a patient has accommodative insufficiency. This deficiency is determined based on an age-related expected finding calculated using Hofstetter's equation derived from Donder's and Duane's data. The aim of the present study was to investigate the amplitude of accommodation among Ghanaian school children and to compare the findings with age-expected norms predicted by Hofstetter's equation. Methods: The amplitude of accommodation was measured using the push-up method in a random sample of 435 school children from the Cape Coast Municipality. The mean amplitude of accommodation was compared with the age-expected amplitude of accommodation as predicted by Hofstetter's equation for average amplitude of accommodation. Results: The mean amplitude of accommodation was 16.86 ± 3.07 D (95% CI = 16.57, 17.15). This is significantly higher than age-expected norms calculated using Hofstetter's equation. The amplitude of accommodation showed the characteristic decline with age. Conclusion: From the results, we conclude that the age-expected norms for amplitude of accommodation using Hofstetter's equation might not be accurate for Ghanaian children.