Small and large field grating acuity versus recognition acuity in different groups of amblyopic patients

Grating acuity was tested in 74 subjects with different amblyopia and five patients with pathological morphological findings, reducing visual acuity. Recognition acuity was tested with Landolt C single symbol and close inter-space 2.6 min. of arc. Grating acuity was tested with the Teller Acuity Cards with large (12.5 cm × 12.5 cm) and small (6.25 cm × 6.25 cm) test fields. Reduction of field size did not cause any significant difference. Patients with strabismic or strabismic and anisometropic amblyopia did not show a close correlation of recognition acuity with grating acuity. Stimulus deprivation amblyopia showed a good correlation between grating acuity (large and small field) and Landolt single optotype acuity. In children at risk for amblyopia, a difference in favour of large field gratings was found for both eyes (risk and non-risk eye) in the lower visual acuity group (identical with the lower age group). Better grating acuity for large fields seems to reflect an early stage of the visual development rather than that it is indicative for amblyopia.