Vision and Attention: Convergence Insufficiency and ADHD

In recent posts we’ve explored the link between vision and movement.   (Vision and Movement and Cranial Nerves) The relationship between vision and movement is natural:  vision is inextricably linked to the brain, both reflecting what the brain is thinking but also regulating sensory inputs.  

Convergence insufficiency (CI) and its connection to attention deficit hyperactivity disorder (ADHD) has been one growing topic in this area.  Convergence insufficiency is the inability to maintain binocular function (keeping the two eyes working together) while working at a near distance.  Quite simply, attentional difficulties may be poor visual focus, which is outside the individual’s control.  Because they can’t adequately express verbally what they are seeing, kids may respond with deviant behavior, which is then labeled as ADHD.   Adults may live with faulty movement habits that resulted from years compensating for undiagnosed visual deficits. 

One of the best ways to demonstrate this is via special goggles that show non CI-sufferers what it is like to have CI.  I can tell you that many old-school thinkers who can’t believe a kids’ poor behavior is linked to vision suddenly become believers when seeing what a truly discombobulated world looks like!

Initial research in this area originally found correlation, but did not explore causation.  Granet (2005) conducted a retrospective study with 266 patients and found 3x more ADHD among CI patients compared to the general population.  Within the ADHD population, there was a 3x greater incidence of CI as well.   Because this was a purely correlative study, they did not explore causation at the time.  Borsting (2005) conducted similar research on twenty four children all with diagnosed CI.  On a standardized behavior test, cognitive problem/inattention, hyperactivity, and ADHD index were significantly higher among the CI kids compared to normative values.

Rouse (2009) studied 261 kids and found that problem behaviors were significantly higher among those with CI and ADHD group compared with the normal binocular vision sample along with a CI sample that was asymptomatic for ADHD.  Authors concluded, “Children with parent report of ADHD or related learning problems may benefit from comprehensive vision evaluation to assess for the presence of convergence insufficiency.”  

Another way to identify the link is by looking at treatment effects.  In general therapeutic treatment has been shown effective in removing CI itself.  (Aziz 2006, Adler 2002, Scheiman 2005).   For CI with ADHD, Chung (2012) studied surgery results and found that surgery for CI resulted in significantly decreased ADHD symptoms in patients with the ADHD trait (though changes were not significant in those without an ADHD trait).  

Barnhart (2012) studied 221 kids and noted children with parent-reported ADHD were more symptomatic (p = 0.005) than those without parent-reported ADHD.  Authors also found significant improvements in vision and performance among patients undergoing treatment.  

Athletic implications

• Biomechanical aspects of poor convergence – CI may leads to compensatory movement and unsafe movement patterns as coping mechanisms to accommodate altered vision.  Problems appearing purely musculoskeletal may also have roots in vision
• Stress regulation - when the world is out of focus, psychological stress increases, along with physical stress from having to work harder on basic tasks
• Attentional focus - kids with medical condition that makes concentrating difficult might be more suited for sprint sports than non-sprint sports.  Vision limitations may also make it difficult for kids to practice in certain domains.  That said, sports may also aid with attention development
• Retained reflex expression - seeing the world literally in chaos may lead to retention of certain primitive reflexes(startle reflex, for example)
• Decision making - How can you objectively evaluate decision making skills if the athlete's vision offers a poor menu from which to choose?

Conclusion
As we’ve noted before, vision is an untapped resource in athletic development.  Though unlikely to make someone faster than they naturally are, treating vision problems can remove restrictions that otherwise limit someone’s potential.  Most importantly, finding the underlying cause for problems, whether in vision or other sensory domains, can facilitate optimal learning in kids otherwise labeled as deviants.  Future research will continue forging connections between vision and performance at sub-clinical levels. 

References
Granet DB,Gomi CF,Ventura R,Miller-Scholte A.  The relationship between convergence insufficiency and ADHD.  Strabismus.2005 Dec;13(4):163-8.

Borsting E,Rouse M,Chu R Measuring ADHD behaviors in children with symptomatic accommodative dysfunction or convergence insufficiency: a preliminary study.  Optometry.2005 Oct;76(10):588-92.

Rouse M,Borsting E,Mitchell GL,Kulp MT,Scheiman M,Amster D,Coulter R,Fecho G,Gallaway M;CITT Study Group.  Academic behaviors in children with convergence insufficiency with and without parent-reported ADHD.  Optom Vis Sci.2009 Oct;86(10):1169-77.

Aziz S, Cleary M, Stewart HK, Weir CR.  Are orthoptic exercises an effective treatment for convergence and fusion deficiencies?  Strabismus.2006 Dec;14(4):183-9.

Adler P.  Efficacy of treatment for convergence insufficiency using vision therapy.  Ophthalmic Physiol Opt.2002 Nov;22(6):565-71.

Scheiman M, Mitchell GL, Cotter S, Cooper J, Kulp M, Rouse M, Borsting E, London R, Wensveen J; Convergence Insufficiency Treatment Trial Study Group.  A randomized clinical trial of treatments for convergence insufficiency in children.  Arch Ophthalmol.2005 Jan;123(1):14-24.

Chung SA,Chang YH,Rhiu S,Lew H,Lee JB.  Parent-reported symptoms of attention deficit hyperactivity disorder in children with intermittent exotropia before and after strabismus surgery.  Yonsei Med J.2012 Jul 1;53(4):806-11. doi: 10.3349/ymj.2012.53.4.806.

Barnhardt C,Cotter SA,Mitchell GL,Scheiman M,Kulp MT.  Symptoms in children with convergence insufficiency: before and after treatment.  Optom Vis Sci.2012 Oct;89(10):1512-20.