Different people can be more or less sensitive to frame rates, and the effect can be reduced or amplified depending on the system/monitor. Many people are fine with 30 FPS, or are only slightly bothered, so there is no reason to get your eyes checked. The same variation in people can be found with first person perspective games (especially where you need to look around while moving), or with the various methods used for 3D movies; some people are fine, some can get headaches or nausea over time (in anywhere from seconds to hours).
