In future, the plan is to test its usefulness for random-dot stereovision determination in infants.Įighteen normal children (mean age, 5.1 ☑.1 years) and 8 children with anisometropic amblyopia (mean age, 4.9 ± 1.3 years), 14 with infantile essential esotropia (mean age, 5.3 ± 0.7 years), and 16 with microstrabismus (mean age, 5.2 ± 1.4 years) were recruited at the Department of Strabismology and Neuro-Ophthalmology of the Kantonsspital St. 15In this study, the new test was used in a larger number of children with normal and abnormal random-dot stereovision and compared to the ability to recognize the Lang I random-dot stereotest. In a previous pilot study including four older children, the testing procedure has been found to be usable in measuring a response to random-dot stimuli objectively in children. We developed a new, 3D monitor–based random-dot test allowing natural viewing conditions with an objective assessment of stimulus recognition using infrared photo-oculography. Easy-to-perform objective tests are necessary for screening of visual dysfunctions in children and for large-scale testing of the development of stereovision. 6 14All the tests designed for preverbal children require some type of dissociating glasses, and some of them allow only subjective testing. Tests that can be used in preverbal children are the Infant Random Dot Stereoacuity Cards, 5the Preschool Randot Stereoacuity Test, 13random-dot stereogram–evoked potentials, and random-dot correlogram evoked potentials. 12All these tests require verbal capabilities from the subject tested. In clinical routine, the most frequently used random-dot tests include the TNO test, the Lang I and II tests, and the Random-dot E test. This lack of monocular cues makes this type of stereogram ideal for stereovision testing. However, if binocularly fused, vivid depth perceptions occur. 8 9 10 11Many testing procedures use the random-dot stereogram, because they convey no visual information other than random noise, if seen monocularly. 1 2 3 4 5 6 7Although the interest of the earlier investigations was predominantly to study the development of stereopsis, later, several studies focused on the measurement of sensory outcomes after the treatment of ophthalmopediatric disorders.
Over the past 25 years, many psychophysical and electrophysiological stereotests have been developed for infants. This new 3D monitor–based test allows objective assessment of random-dot stereopsis in children older than 3 years. Twenty-four of 26 Lang I–positive children had positive responses (sensitivity of 92.3%), 29 of 30 Lang I–negative children had negative three-dimensional (3D) stimulus responses (specificity, 96.7%). The results with the new test were compared with the ability to recognize the Lang I random-dot stereotest. If two or more consecutive saccades ends corresponded to the stimulus coordinates, a positive response was assumed. While the position of the stimulus randomly changed among four possible locations, eye positions were recorded by infrared photo-oculography. Random-dot circles (diameter 10 cm, crossed disparity of 0.34°) were generated on an autostereoscopic display and presented to 18 normal children (mean age, 5.1 ± 1.1 years), 8 with anisometropic amblyopia (mean age, 4.9 ± 1.3 years), 14 with infantile essential esotropia (mean age, 5.3 ± 0.7 years), and 16 with primary microstrabismus (mean age, 5.2 ± 1.4 years). For this reason, a new, natural method for random-dot stereopsis measurement was developed and tested. Drawbacks of such methods are the alteration of natural visual conditions and sometimes nonacceptance of the glasses. Objective testing for random-dot stereovision in preverbal children requires some type of dissociating glasses.