VEP LATENCY - A COMPARISON BETWEEN NORMAL AND DEFECTIVE BINOCULARITY

1. The aim of this study was to determine if transient pattern reversa l VEP latency is influenced by binocular function, and to explore the possibilities of using this parameter for objective assessment of bino cularity. 2. VEP latency was measured in ten normal individuals, and i n five stereoblind subjects. Reversing sinusoidal gratings with spatia l frequencies 4 and 8 c/deg and contrast levels of 1.0, 0.316 (=0.5 lo g units below 1.0) and 0.1, respectively, were used. For each pattern, measurements were made for each eye separately, and then binocularly. The difference between binocular and monocular latency was calculated . 3. For normals, the average VEP latency was significantly shorter du ring binocular than during monocular viewing at 4 c/deg, contrast 1.0 and 0.316. The stereoblind group showed no such shorter binocular late ncy. The average binocular-monocular latency difference in the normal group was significantly different from that in the stereoblind group. 4. Transient pattern VEP latency is influenced by binocular dysfunctio n, expressed as absence of stereo vision. The results indicate that bi nocular-monocular VEP latency difference may be used for assessing bin ocular functions.