Considering the experiments conducted, at least in some cases the LF observed appear to be caused by activation of neurons along the visual pathway, resulting in phosphenes. However, because the researchers cannot definitively rule out the Cherenkov radiation effects as a probable cause of the LF experienced by astronauts, it seems likely that some LF may be the result of Cherenkov radiation effects in the eye itself, instead. The Cherenkov effect can cause Cherenkov light to be emitted in the vitreous body of the eye and thus allow the person to perceive the LF. Hence, it appears that the LF perceived by astronauts in space have different causes. Some may be the result of actual light stimulating the retina, while others may be the result of activity that occurs in neurons along the visual pathway, producing phosphenes.