title: Amblyopia in astigmatic infants and toddlers.
abstract: OBJECTIVE
  To determine whether reduced astigmatism-corrected acuity for vertical (V) and/or horizontal (H) gratings and/or meridional amblyopia (MA) are present before 3 years of age in children who have with-the-rule astigmatism.
  
  
  METHODS
  Subjects were 448 children, 6 months through 2 years of age with no known ocular abnormalities other than with-the-rule astigmatism, who were recruited through Women, Infants and Children clinics on the Tohono O'odham reservation. Children were classified as non-astigmats (< or =2.00 diopters) or astigmats (>2.00 diopters) based on right eye non-cycloplegic autorefraction measurements (Welch Allyn SureSight). Right eye astigmatism-corrected grating acuity for V and H stimuli was measured using the Teller Acuity Card procedure while children wore cross-cylinder lenses to correct their astigmatism or plano lenses if they had no astigmatism.
  
  
  RESULTS
  Astigmatism-corrected acuity for both V and H gratings was significantly poorer in the astigmats than in the non-astigmats, and the reduction in acuity for astigmats was present for children in all three age groups examined (6 months to <1 year, 1 to <2 years, and 2 to <3 years). There was no significant difference in V-H grating acuity (no evidence of MA) for the astigmatic group as a whole, or when data were analyzed for each age group.
  
  
  CONCLUSIONS
  Even in the youngest age group, astigmats tested with astigmatism correction showed reduced acuity for both V and H gratings, which suggests that astigmatism is having a negative influence on visual development. We found no evidence of orientation-related differences in astigmatism-corrected grating acuity, indicating either that MA does not develop before 3 years of age, or that most of the astigmatic children had a type of astigmatism, i.e., hyperopic, that has proven to be less likely than myopic or mixed astigmatism to result in MA.
authors.affiliation: Department of Ophthalmology and Vision Science, The University of Arizona, Tucson, Arizona, USA.
authors.forename: Velma
authors.initials: V
authors.lastname: Dobson
authors.forename: Erin M
authors.initials: EM
authors.lastname: Harvey
authors.forename: Candice E
authors.initials: CE
authors.lastname: Clifford-Donaldson
authors.forename: Tina K
authors.initials: TK
authors.lastname: Green
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miller
mesh_terms: D000550:Amblyopia / Q000209:etiology* / Q000503:physiopathology / Q000534:rehabilitation; D001251:Astigmatism / Q000150:complications* / Q000503:physiopathology / Q000534:rehabilitation; D002675:Child, Preschool; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D011379:Prognosis; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology