Clinical norms for amplitude of accommodation in Chinese.

Amplitude of accommodation was measured in 121 Hong Kong Chinese subjects between the ages of 11 and 65 years, using the 'push-up' method and the results compared with those previously obtained for Caucasian subjects. The results confirm and quantify clinical experience that Chinese people have lower amplitudes of accommodation than Caucasians. If presbyopia is considered to commence when the amplitude of accommodation declines to less than 5 D, then presbyopia in the Chinese race occurs between the ages of 36 and 40 years. By early in the second decade of life the amplitude of accommodation in the Chinese is already lower than that of Caucasians. This suggests that reduced amplitude of accommodation may be due, at least in part, to factors other than longterm environmental effects.