Random-dot stereopsis in microstrabismic children: stimulus size matters.

Purpose: Although children with microstrabismus demonstrate stereoscopic abilities when assessed with clinical tests containing visible contours (local stereopsis), severe stereoscopic impairments are reported when using random-dot stereogram (RDS). This differential performance may be associated with the decreasing interocular correlation resulting from the central suppression present in the deviated eye, affecting global stereopsis to a greater extent.

Methods: To test this hypothesis, stereoscopic performance on tasks using contour/local (experiment 1), RDS depth (experiment 2), and RDS shape discrimination (experiment 3) was obtained in nine microstrabismic children and compared with that of control participants.

[Local and global stereopsis in children with microstrabismus].

Introduction: It is generally accepted that stereopsis is present in patients with microstrabismus, although it is reduced. This concept relies primarily on the evaluation of local stereopsis, which contains visible monocular cues. However, microstrabismic patients seem to present much more impairment in identifying the global form in random dot stereograms (global stereopsis).

Effect of aging on stereoscopic interocular correlation.

Purpose: This study was designed to evaluate the minimum interocular correlation (IOC) needed by the visual system to correctly perceive a static stereoscopic stimulus as a function of normal aging. It was also our goal to evaluate the feasibility of clinical charts testing this aspect of visual perception.

Methods: Stereoscopic IOC threshold was determined in 100 normal observers (average age +/- standard deviation, 45.

Spasm of the near reflex triggered by disruption of normal binocular vision.

A 26-year-old healthy female was referred by her optometrist to the binocular vision clinic of our institution for the investigation of an accommodative spasm occurring during monocular conditions. Corrected binocular visual acuity was 20/20 (6/6), with normal pupils and good ocular alignment. When the fellow eye was covered, visual acuity was <20/200 (6/60) in each eye, miosis was present in both eyes, and the occluded eye was in esodeviation, indicating a spasm of the near reflex.