title: Does ethnicity influence the short-term adaptation to first reading correction?
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  The pattern of adaptation by accommodation and cross-link interactions to short-term first reading spectacles is not influenced by ethnicity.
authors.affiliation: Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627-0268, USA. ivedamurthy@bcs.rochester.edu
authors.forename: Indu
authors.initials: I
authors.lastname: Vedamurthy
authors.forename: Meng
authors.initials: M
authors.lastname: Lin
authors.forename: Jianliang
authors.initials: J
authors.lastname: Tong
authors.forename: Thao N
authors.initials: TN
authors.lastname: Yeh
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Graham
authors.forename: Harry
authors.initials: H
authors.lastname: Green
authors.forename: Shiyin Linda
authors.initials: SL
authors.lastname: Wang
authors.forename: Amrita
authors.initials: A
authors.lastname: Sabharwal
authors.forename: Clifton M
authors.initials: CM
authors.lastname: Schor
mesh_terms: D000065:Accommodation, Ocular; D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D005006:Ethnicity; D005139:Eyeglasses; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000208:ethnology* / Q000503:physiopathology / Q000628:therapy; D015995:Prevalence; D011932:Reading; D013997:Time Factors; D014481:United States / Q000453:epidemiology