Purpose: Amplitude of accommodation varies with race and ethnicity and Hofstetter's equations are commonly used in Nigeria to calculate expected amplitude of accommodation for clinical purposes. The aim of this study was to present normative values for amplitude of accommodation for Nigerian children and to compare the measured values with those calculated using Hofstetter's equations.
Methods: A total of 688 children aged six to 16 years from three selected cities in Nigeria were included in the study. Push-up technique was employed to measure the amplitude of accommodation. The measured values were compared with the calculated values (Hofstetter's equations) using the paired t-test and Bland and Altman plots.
Results: The measured amplitude of accommodation for the subjects ranged from 8.00 to 25.00 D with a mean of 15.88 ± 3.46 D. The calculated minimum amplitude of accommodation ranged from 11.00 to 13.50 D with a mean of 12.09 ± 0.55 D and the calculated average amplitude of accommodation ranged from 13.17 to 16.50 D with a mean of 14.62 ± 0.73 D. The calculated maximum amplitude of accommodation ranged from 18.60 to 22.60 D with a mean of 20.34 ± 0.88 D. The t-test indicated a significant difference between the measured and calculated minimum, average and maximum amplitudes of accommodation (p < 0.0001). Also, the Bland-Altman plot suggested that there was a lack of agreement between the measured and calculated amplitudes of accommodation.
Conclusion: The mean values of amplitude of accommodation in this study are different from those reported in the literature. Also, the measured values differed from the calculated values using Hofstetter's equation. This suggests that the use of Hosftetter's equations to predict amplitude of accommodation may not be accurate for Nigerian children.
Keywords: Hofstetter; Nigerians; accommodation; children; presbyopia; reading.
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