Resistance to occlusion: sensitivity to induced blur in 6- to 12-month-old infants

J Am Optom Assoc. 1994 Sep;65(9):651-9.


Background: Resistance to occlusion and fix and follow are often used to make inferences about the acuity of young children. In this study, the acuity of 6- to 12-month-old infants was degraded monocularly to elicit resistance to occlusion or loss of fixation.

Methods: Occlusion foils and optical blur were used to simulate monocular acuity reduction. Two different targets, a mechanical rabbit and a "flickering" light were used for fixation.

Results: More infants resisted occlusion when viewing the rabbit than the light. Resistance to occlusion was observed in the majority of infants when acuity was degraded to the level expected for 6 to 12-month-old infants (20/80-20/300).

Conclusions: The sensitivity of resistance to occlusion is influenced by the test target and if an interesting target is used, resistance to occlusion may be a useful tool for detecting interocular acuity differences in 6- to 12-month-old infants.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amblyopia / diagnosis
  • Amblyopia / physiopathology
  • Child, Preschool
  • Fixation, Ocular / physiology*
  • Humans
  • Infant
  • Sensory Deprivation*
  • Vision Tests / methods
  • Vision, Monocular / physiology
  • Visual Acuity / physiology*