Population receptive field (pRF) mapping is an advanced retinotopic mapping approach. While the size of pRFs has been identified as an important neurophysiological feature, remarkable differences in the pRF sizes across studies has been reported. In this study, we examine the effects of difference in spatial resolution on the pRF size obtained in a group of ten healthy subjects at 7T. Our results clearly show that the amount of spatial dependence between voxels in the visual cortex has a direct effect for the pRF sizes calculated. We can assume similar effects in data sets acquired at different spatial resolutions.