<prompt> Answer this question truthfullyWhat is the Rule of the Pupil and what medical conditions are suggested by a CN3 lesion with pupil dilation, and a CN3 lesion without pupil dilation?  <response>: <reason> The Rule of the Pupil is a diagnostic tool used to identify the potential causes of a CN3 lesion. A CN3 lesion with pupil dilation is suggestive of a PCOM aneurysm, while a CN3 lesion without pupil dilation is suggestive of diabetes. 