Accuracy and validity of IK4 handheld video keratometer measurements in children.

The infant keratometer (IK4) is a custom handheld instrument that was designed specifically to allow measurement of corneal astigmatism in infants as young as 6 months of age. In this study, accuracy of IK4 measurements with the use of standard toric surfaces was within 0.25 D.

Prevalence of corneal astigmatism in Tohono O'odham Native American children 6 months to 8 years of age.

Purpose: To describe the prevalence of corneal astigmatism in infants and young children who are members of a Native American tribe with a high prevalence of refractive astigmatism.

Methods: The prevalence of corneal astigmatism was assessed by obtaining infant keratometer (IK4) measurements from 1235 Tohono O'odham children, aged 6 months to 8 years.

Results: The prevalence of corneal astigmatism >2.

Prevalence of astigmatism in Native American infants and children.

Purpose: To describe the prevalence of high astigmatism in infants and young children who are members of a Native American tribe with a high prevalence of astigmatism.

Methods: SureSight autorefraction measurements were obtained for 1461 Tohono O'odham children aged 6 months to 8 years.

Results: The prevalence of astigmatism >2.

Amblyopia in astigmatic infants and toddlers.

Purpose: 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.

Accuracy of the Welch Allyn SureSight for measurement of magnitude of astigmatism in 3- to 7-year-old children.

Purpose: To evaluate the accuracy of the Welch Allyn SureSight in noncycloplegic measurements of astigmatism as compared to cycloplegic Retinomax K+ autorefractor measurements of astigmatism in children from a Native American population with a high prevalence of high astigmatism.

Methods: Data are reported for 825 3- to 7-year-old children with no ocular abnormalities. Each child had a Retinomax K+ cycloplegic measurement of right eye astigmatism with a confidence rating > or =8 and 3 attempts to obtain a SureSight measurement on the right eye.

Normative monocular visual acuity for early treatment diabetic retinopathy study charts in emmetropic children 5 to 12 years of age.

Objective: To provide normative data for children tested with Early Treatment Diabetic Retinopathy Study (ETDRS) charts.

Design: Cross-sectional study.

Participants: A total of 252 Native American (Tohono O'odham) children aged 5 to 12 years.

Optical treatment reduces amblyopia in astigmatic children who receive spectacles before kindergarten.

Objective: To examine the effect of spectacle correction of astigmatism during preschool on best-corrected recognition visual acuity (VA), grating VA, and meridional amblyopia (difference between acuity for vertical versus horizontal gratings) once the children reach kindergarten.

Design: Comparative case series.

Participants: Seventy-three astigmatic (right eye > or =1.