Amblyopia in Astigmatic Infants and Toddlers

Abstract

Purpose To determine if reduced astigmatism-corrected acuity for vertical (V) and/or horizontal (H) gratings and/or meridional amblyopia (MA) are present prior to age three years 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 (≤ 2.00 D) or astigmats (> 2.00 D) based on right eye (RE) non-cycloplegic autorefraction measurements (Welch Allyn SureSight). RE 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, 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 prior to age 3 years, 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.

To prescribe or not to prescribe? Guidelines for spectacle prescribing in infants and children

“…The visual system may not be very sensitive to uncorrected astigmatism in the first year of life 54 but from one year onwards, there is evidence that uncorrected astigmatism, particularly oblique astigmatism, is associated with meridional amblyopia 20,25,55 . Dobson and colleagues 56 found no evidence of meridional amblyopia in six‐month‐olds up to three‐year‐olds with astigmatism of 2.00 D or more, although the acuity for both vertical and horizontal gratings was decreased in children with astigmatism, which may be because most of the children with astigmatism were also hyperopic. In three‐ to four‐year‐olds, 1.50 D or more of astigmatism is associated with poorer recognition acuity, such that for every dioptre increase in cylinder, there was a half‐line decrease in VA 57 .…”

The profile of astigmatism in 6–12-year-old children in Iran

“… 7 , 8 Second, the presence of marked astigmatism during the development of the visual system can cause meridional amblyopia in children. 9 , 10 Finally, this type of refractive error may disturb emmetropization due to producing a blurred image on the retina. 11 , 12 Other studies have shown that uncorrected astigmatism can result in the formation or progression of myopia, as well.…”

“… 11 , 13 , 14 Most changes due to astigmatism and its effects, especially its amblyogenic and myopigenic nature, are observed in individuals under 15 years of age. 9 , 15 , 16 …”

Genome-Wide Meta-Analysis of Five Asian Cohorts Identifies PDGFRA as a Susceptibility Locus for Corneal Astigmatism

“…While astigmatism comprises cornea and non-corneal components, it typically results from the unequal curvature of two principle meridians in the anterior surface of the cornea known as corneal astigmatism [1] , [2] . The presence of a high degree of astigmatism during early development is believed to be associated with refractive amblyopia [3] , [4] , [5] , as evidenced by decreased best-corrected visual acuity which cannot be remedied by external corrective lenses. Early abnormal visual input caused by uncorrected astigmatism can lead to orientation-dependent visual deficits, despite optical correction of visual acuity later in life [6] .…”