Ethnic variations in accommodative amplitude (AA) are not uncommon. Accommodation
can become reduced in response to short-term wear of first near spectacles
. Whether ethnicity
has an influence on the magnitude of this adaptation
is not well understood. We investigated the impact of first near spectacles
on changes in AA and on convergence
cross-link interactions in incipient presbyopes of Chinese and Caucasian ethnicities.
Forty-one subjects (22 Caucasians and 19 Chinese) aged 36 to 44 years completed the study. Accommodative stimulus response function, AA, and AC/A and CA/C ratios were measured before and after single vision reading spectacles were used for near tasks over a 2-month period and then again 2 months after discontinuing near spectacle wear.
After wearing reading spectacles for 2 months, the accommodative stimulus response slopes and AC/A and CA/C ratios remained invariant irrespective of ethnicity
. The accommodative, but not vergence, bias decreased (p < 0.05). The nearpoint of accommodation
shifted distally producing an average decrease in AA of 0.52 D from baseline (p < 0.05). Recovery to near baseline values occurred after discontinuing the reading glasses for 2 months. Differences based on ethnicity
were not significant. The baseline AA vs. age plots showed steeper slopes for Chinese than the Caucasian subjects in the sample.
The pattern of adaptation
and cross-link interactions to short-term first reading spectacles is not influenced by ethnicity