Design and Validation of a Method for Evaluation of Interocular Interaction

Abstract

The TFA may provide an acceptable method for the study of some forms of dichoptic masking in populations where more complex devices (e.g., shutter goggles) cannot be used.

A novel apparatus for interocular interaction evaluation in children with and without anisometropic amblyopia

“…The occluder was made using a +5.00 DS trial lens, on which four strips of 5.0 mm wide opaque black masking tape were placed to form a ‘star‐shaped’ occlusion (Figure 1). Visual function and interocular interaction measurements made using this method were found to agree with those made using shutter goggles in children and adults with normal vision 14 …”

“…The limits of agreement and the number of subjects showing differences beyond these limits and the results of agreement assessment between these two viewing systems (Bland‐Altman and t‐test methods) are shown in Table 2. The agreement between these two viewing systems in control subjects is discussed elsewhere 14 …”

“…The design and validation of the TFA (Figure 1) are described elsewhere 14 . In both full and partial occlusion, a pinhole aperture (1.0 mm in diameter) was placed in front of the tested eye.…”

“…The star‐shaped occluder consisted of one opaque black masking tape at horizontal, one at vertical and the other two at 45° and 135°. Depending on the vertex distance, the opaque occlusion at the centre of the star‐shaped occluder blocked out between 22° and 24° of the central visual field of the non‐tested eye but light transmission from the periphery was allowed 14 . The pinhole transmits approximately 10° of central field to the tested eye and the field more peripheral to this was vignetted.…”

“…Mirror or prism devices and shutter goggles have been used in dichoptic masking studies; 3,11–13 however, equipment of this kind may not be feasible for use in some populations 14 . For this reason, a simple and portable viewing system, a ‘trial frame apparatus’ (TFA) was designed and validated in a previous study 14 . The TFA consisted of a trial frame adjusted to the individual's interpupillary distance, a pinhole aperture (1.0 mm in diameter) placed in front of the tested eye and a partial occluder placed in front of the non‐tested eye.…”