Journal of Novel Physiotherapies
Open Access

Attention Deficit Hyperactivity Disorder (ADHD) is considered a common health problem in children, teenagers [1] and adults [2], with worldwide prevalence of 5.3% in school-aged children [3], reaching 50% in the adulthood [2]. Several works have been showing that the circuits related with attention control are altered in individuals with ADHD [4,5], suggesting modulations on the fronto-striatal-cerebellar axis [3,4], as well as on cortex association areas [4], frontal lobe and subcortical areas [3], which modulate cognitive and behavioral circuits. Traditionally, the basal ganglia inhibitory circuits are in part responsible for the preparation and unconscious programming of four strategies: (1) somatomotor; (2) oculomotor; (3) cognitive and (4) limbic [6], in some extent explaining the complex clinic presentation of ADHD.

Ocular convergence movement is defined as the ability in performing an eyes conjugated abduction while aiming at an only target (Figure 1) [2,7]. Ocular Convergence Insufficiency (OCI) represents a multifactorial problem of binocular vision, characterized by the inability in performing this conjugated movement (Figure 2) [8]. Described for the first time in 1855, OCI has been addressed in several studies aiming at estimating its etiology, prevalence, clinical signs and diagnostic [8]. In a functional perspective the OCI is related to attention levels [9], cognition, memory and behavior [10] processed in basal ganglia circuits [6], which may result in mutual decompensation.

Figure 1: Movement of normal ocular convergence in a woman adult.

Figure 2: Ocular convergence insufficiency in a man adult.

Since the first papers [11] and in recent studies [2,10,12-19], OCI has been suggested to have significant correlation with ADHD, as well as frequency and severity of learning, reading or attention disorders.

For over a decade, some diagnostic criteria for ADHD [2] and OCI [9] have been showed to be correlated [10]. Since then this subject became of great relevance for researchers worldwide [2,10,12-22]. Therefore, the possibility of a relation between ADHD and OCI has been discussed [10,19,22-24]. A 12-weeks vision therapy for OCI correction showed a significant decrease in symptoms related to ADHD in more than a thousand children [23,24].

More recently, it was validated a clinical assessment for OCI in children with ADHD considering the presence of this ocular disorder as a relevant marker for ADHD diagnostic [22].

This ocular evaluation is simple, cheap, safe and does not offer risks, being easily performed with a pen. We suggest that every individual (children, teenagers and adults) with ADHD suspect should have their ocular convergence assessed, and those who present a convergence proximal point equal or greater than 5 centimeters (Figure 3) [19,21,23,24] must be treated before any drug intervention [25].

Figure 3: Evaluation of near point ocular convergence with optometric ruler in a child (Bernell^®).