Near Point Of Fixation Disparity (NPFD) And It's Association With Concussive Injury.

Background: The Rinkside Concussion Investigator Group was formed to investigate the protocol for removing an athlete from play when a potentially concussive injury has occurred. The Near Point of Fixation Disparity (NPFD) test is an assessment
that has shown promise in the area of concussion determination. This research was
seeking to determine normative values for the NPFD test. It was designed to supplement ongoing investigations of the use of the NPFD test with the goal of determining if the test can be used for rink/sideline concussion screenings during sporting events.
Methods: The NPFD test requires the subject to view a card with polarized nonius lines while wearing polarized glasses. While focusing on the central E target, the near point of
fixation disparity card is moved slowly inward toward the subject's nose. As the target
approaches the subject, they report when the vertical nonius lines become horizontally
misaligned. The distance, measured from the spectacle plane to the card, at which this
misalignment occurs indicates the NPFD breakpoint. As the target is moved back toward the start point, the distance at which the lines become re-aligned is recorded as the recovery point.
Results: The goal of this study was to begin to establish a range of NPFD normal values. Studies have shown that a reduced near point of fixation disparity is associated with history of a concussion. The immediate effect of a concussion on near point of fixation disparity breakpoint and recovery has not yet been researched.
Conclusions: Establishing normal findings for the NPFD test is an important step in determining if this test can be used on athletes who have had a suspected injury. This
research and further research using this data will be beneficial to the sports community in providing a quick, easy and reliable assessment to make return-to-play decisions.