Purchase this article with an account.
E.M. Harvey, V. Dobson, J.M. Miller, C.E. Clifford; Accommodation in Uncorrected Astigmatic Children . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2727.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Myopic/mixed astigmatic children demonstrate meriodional amblyopia, whereas hyperopic astigmatic children demonstrate equivalent amblyopia across stimulus orientation (Dobson et al., in press). These data suggest that hyperopic astigmats may accommodate to focus between the anterior and posterior focal planes, and thus experience blur for both stimulus orientations. We evaluated accommodation in children with uncorrected hyperopic astigmatism to better understand the nature of their early visual experience. Methods: Non-cycloplegic autorefraction was performed on the right eye (RE) of 5th and 6th grade children using the Grand Seiko WR-5100K open field binocular autorefractor while each child viewed each of 3 targets (ETDRS acuity chart, astigmatism wheel, photo of a child) at distance (4 m) and at near (40 cm). A best estimate of refractive error (BER) was determined through subjectively refined cycloplegic autorefraction (Nikon Retinomax K+), and 12 subjects with hyperopic astigmatism were selected for analysis based on their BER (RE cylinder ≥ +1.00D, sphere ≥ 0.00D). We predicted that uncorrected autorefraction measurements of spherical equivalent (SE) for astigmatic subjects should be close to 0D when viewing distant targets and close to –2.50D when viewing near targets if subjects are focusing between anterior and posterior focal planes. More positive measures of SE (relative to 0 at distance and –2.50D at near) would indicate that the anterior focal plane is in better focus, and more negative measures would indicate that the posterior focal plane is in better focus. Results: Measurements across target type were averaged for each test distance. The mean SE for distant targets was 2.05D (SD=1.23, range = +0.13 to +4.58). The mean SE for near targets was 0.30D (SD=1.68, range = -1.79 to +3.06). Measurements at both distance and near indicate that the anterior focal plane was in better focus. Conclusions: These data are not consistent with the idea that hyperopic astigmats’ non-meridional amblyopia is due to accommodative strategies that cause both anterior and posterior focal planes to be equally out of focus, but are consistent with data from adult subjects (Freeman et al., 1975) that indicate that uncorrected hyperopic astigmats tend to experience the more anterior focal plane in focus.
This PDF is available to Subscribers Only