Abstract
Purpose: :
Objective testing for random–dot stereovision in preverbal children requires some type of dissociating glasses. Drawbacks of such methods are the alteration of natural visual conditions and non–acceptance of the glasses. Therefore, a new, natural method to objectively measure random–dot stereopsis in children has been developed and tested.
Methods: :
Random–dot circles (diameter 5 cm, crossed disparity of 0.34°) were generated on an autostereoscopic display and presented to 18 normal children (age 5.1 +/–1.1 years), 8 with anisometropic amblyopia (age 4.9 +/– 1.3 years), 14 with infantile essential esotropia (age 5.3 +/– 0.7 years), and 16 with primary microstrabismus (age 5.2 +/– 1.4 years). While the stimulus was randomly changing its position between four possible locations, eye positions were registered by infrared photo–oculography. If two or more consecutive saccades ends corresponded to the stimulus coordinates, a positive response was assumed. The results with the new test were compared to the ability to recognize the Lang I random–dot stereotest.
Results: :
29 of 30 Lang I negative children (96.7 %) had negative 3D stimulus responses, 24 of 26 Lang I positive children (92.3%) had positive responses. The positive predictive value of the new test is 0.96 (95% CI 0.85–0.99), the negative predictive value 0.94 (95% CI 0.85–0.96).
Conclusions: :
This new examination technique allows an objective assessment of random–dot stereopsis in children. The method might open new ways to screen children for visual abnormalities. If applicable to preverbal children, it may permit to study the development of stereovision under natural conditions.
Keywords: strabismus: diagnosis and detection • space and scene perception