Repetitive head trauma—even if it isn’t strong enough to bring on a full-fledged concussion—could cause one’s vision to blur slightly, according to a study that included 29 NCAA football players.

Dianne Langford, PhD, from Temple University in Philadelphia and her team examined whether the incidence of repetitive subconcussive head impacts during preseason football practice caused any changes among these NCAA Division 1 football players.

An accelerometer-embedded mouthguard that the players wore measured the players’ head impact kinematics during baseline and preseason practices (one noncontact and four contact). Based on the total number of head impacts (1,193) from all five practices, the researchers categorized the players into lower or higher impact groups, according to a media release from The JAMA Network Journals.

In total, 22 players were categorized in the high-impact group, and 7 were categorized into the low-impact group. After studying the results, the team observed significant differences in head impact kinetics between lower-and higher-impact groups.

These repetitive subconcussive impacts were associated with changes in near point of convergence (NPC) ocular-motor function among players in the higher-impact group, although NPC was normalized after a 3-week rest period. The NPC measures the closest point to which one can maintain convergence (simultaneous inward movement of eyes toward each other) while focusing on an object before diplopia (double vision) occurs, the release explains.

“The increase in NPC highlights the vulnerability and slow recovery of the ocular-motor system following subconcussive head impacts. Changes in NPC may become a useful clinical tool in deciphering brain injury severity,” says Langford, in the release.

The study was published recently in JAMA Ophthalmology.

[Source(s): The JAMA Network Journals, EurekAlert]