Human Basement Membrane Components of Keratoconus and Normal Corneas

tern may possess fusional capacity that allows compensation for small perceived retinal size differences, but when the difference exceeds a certain level, the binocular system is unable to fuse these perceived image differences and may function as binocular inhibition resulting in a smaller binocular than monocular VER amplitude. Our results show that the binocular system may be able to compensate for a perceived retinal image size difference between two eyes of up to 3.0%. Although a direct comparison cannot be made, our results are in good accordance with those obtained from psychophysical and clinical studies. Whereas Lovasik and Bishop reported that simulated aniseikonia did not affect the amplitude and implicit time of transient pattern reversal VER, we found steady-state pattern reversal VER very sensitive to the perceived retinal image size differences between two eyes. An abnormal degree of binocular summation suggests defective binocular function. However, asthenopia and headache can be observed in patients with passable VER examination. Further clinical studies are required to clarify these findings. We suggest that pattern reversal VER may be helpful in evaluating visual function, especially binocular function of pediatric subjects in whom subjective methods are of limited use.