[Critical frequency of light flickering rhythm reproduction in visual evoked potentials: physiological essence of the...

Critical frequency of light flickering rhythm reproduction in visual evoked potentials (CFLF) was studied in 25 patients (35 eyes) with partial optic nerve atrophy, 4 patients (7 eyes) with moderate changes in the optic route suprachiasmal sections, and 23 normal subjects; automated static perimetry and visometry were carried out as well. CFLF was found reduced in the majority of patients with optic nerve atrophy, whereas in suprachiasmal involvement this parameter remained within the normal range. CFLF values were in good correlation with vision acuity and light sensitivity of visual field sites within the angle of 15 degrees from the center (the correlation was higher for foveal light sensitivity when it was expressed in relative units, and for light sensitivity of paracentral visual field sites when expressed in logarithmic units). The authors come to a conclusion that CFLF functional and anatomic substrate is the foveal area cortical projection sites and, to a lesser degree, cortical projection sites of visual field sites within 15 degrees from the center; in optic nerve atrophy CFLF values depend on the status of the optic nerve sections (the axial bundle) corresponding to a certain visual field site.