Abstract
Stereoscopic depth perception may be obtained from small retinal disparities that can be fused for single vision (fine stereopsis), but reliable depth information is also obtained from larger disparities that produce double vision (coarse stereopsis). The role of coarse stereopsis in vision is not well understood, but it may develop early in life to guide vergence eye movements that are necessary for the development of fine stereopsis. While there is some evidence that stereoacuity improves with age, little is known about the development and maturation of coarse stereopsis. The purpose of this study was to determine the age at which performance on fine and coarse stereoscopic tasks reaches adult levels during typical visual development. We compared performance in children (4-13 years) and adults on computerized tests of fine and coarse stereopsis. All participants had normal visual acuity, normal stereoacuity and no ocular pathology. Stereoscopic stimuli were presented using liquid crystal shutter glasses. The observer’s task was to indicate whether a cartoon character was nearer (crossed disparity) or farther away (uncrossed disparity) than a zero-disparity fixation marker. We assessed perceived depth for a set of fine disparities that were within Panum’s fusion zone (0.02, 0.08, 0.17, 0.33, 0.67, 1 degrees) and a set of coarse disparities that appeared diplopic (2, 2.5, 3, 3.5 degrees). Accuracy increased with disparity in the fine range and decreased slightly with disparity in the coarse range for all participants. Within the coarse range, there were no differences between age groups. However, performance was immature until age 12, at the finest disparity tested; adult levels were reached at different ages across the other disparities in the fine range. These results suggest that coarse stereopsis matures before 4 years of age, but fine stereopsis continues to mature into the school-age years.
Meeting abstract presented at VSS 2012