Association of Football Subconcussive Head Impacts With
Ocular Near Point of Convergence
K, Rubin LH, Lee JH, Sim T, Takahagi M, Szwanki V, Bellamy A, Darvish K, Assari
S, Henderer JD, Tierney R, Langford D. JAMA Ophthalmol. 2016; ahead of print
Take Home Message: Football
players with significant subconcussive impacts had impaired near point
convergence before and after full contact practices compared with baseline
scores. Football players with less intense head impacts showed no changes over
time. Near point convergence may be a useful clinical tool to implement in sports
at risk for subconcussive impacts. 
head impacts occur more frequently than concussive blows and may cause
long-term neurological deficits. However, there are no clinical tools to detect
the neurological consequences of subconcussive head impacts within one sport
season. Therefore, the authors assessed whether repetitive subconcussive head
impacts during preseason collegiate football is associated with changes in near
point convergence (a measure of the closest point someone can follow an object
coming towards their face). The authors collected head impact kinematic data, near point convergence measurements, and
SCAT3 sign and symptom scores during preseason physical examination (June 2015),
before and after 1 noncontact and 4 full-contact football training camp
practices (3 to 4 days in between), and 3 weeks after the final game. Based on
the 5-practice kinematic impact data the authors categorized the athletes into
a low impact group (7 athletes) and a high impact group (22 athletes). To
measure near point convergence the athlete was seated with the near point
convergence ruler placed on the athlete’s upper lip and they focused on a
reduced size Snellen chart as it moved toward their face. The near point
convergence measurement was taken when the athlete said that the chart went
double or the tester observed eye misalignment. There were no differences
between impact groups and their demographic data (age, BMI, years of
experience, concussion history). Both groups had similar near point convergence
at baseline. However, the higher-impact group had greater worsening over time
that resolved by the post-season time point. Conversely, the lower-impact group
had no change in near point convergence overtime. There was no change in sign
and symptom scores between groups or from preseason to post season.
the authors found that repetitive subconcussive head impacts might compromise
near point convergence function without athletes reporting changes in symptoms.
However, this only occurred in the high impact group, which was exposed to a
greater number and magnitude of impacts. The decline started with the pads-on
practices, which is not surprising because this is when contact practices
begin. It was alarming to see the decline worsen across the contact practices. Fortunately,
these players showed improved near point convergence after a 3-week rest period
after the season. This may suggest that ocular-motor function could reflect
subclinical brain damage and recovery. It will be interesting to see if future
studies confirm these findings, especially among studies that perform baseline
testing closer to the start of football training camp practices. Healthcare
professionals, athletes, and parents should be aware of the potential harm to
the ocular-motor system from subconcussive blows. Though further research is
necessary to investigate the clinical relevance, the authors demonstrate that
adding a near point convergence measurement to a baseline concussion protocol
could be beneficial in assessing subclinical concussions.
Questions for Discussion:
Should we be monitoring head impacts? Are you using near point convergence in
your concussion protocol? Do you believe these subclinical concussions/subconcussive
impacts will cause long-term effects?
by: Jane McDevitt, PhD
by: Jeff Driban