Accommodative insufficiency (AI) involves the inability of the eye to focus properly on an object.
Accommodative insufficiency is a sensory motor anomaly of the visual system that is characterized by an inability to focus or sustain focus at near, demonstrated clinically by an insufficient amplitude of accommodation based on age-expected norms.
Scheiman et al in a study that included 2,023 pediatric patients found 19.7% to suffer from a binocular or accommodative dysfunction. This was broken down further into convergence excess (7.1%), convergence insufficiency (4.6%), accommodative insufficiency (2%) and accommodative excess (1.8%).
Accommodative insufficiency is commonly present in people with convergence insufficiency. An understanding of the close association between accommodative function and convergence is important. When patients accommodate, convergence occurs, and when they converge they also accommodate. This relationship can be quantified by the AC/A (Accommodative Convergence/Accommodation) and CA/C (Convergence Accommodative/Convergence) ratios, respectively. Accommodative and convergence insufficiency typically present at the same time, a likely result of a neurological link. The rate of co-morbidity has been shown to increase with the severity of the convergence insufficiency.
Symptoms of Accommodative Insufficiency begin almost simultaneously with an increase in near work demand. It is common as school age children encounter more desk work and when the font size on worksheets and in text books gets smaller. Many parents note that the amount of near work that children perform on a daily basis has increased ten-fold from when the parents were young. Students are expected to do more near work and at a more demanding level than ever before. Research has shown that some children, especially under the age of 8, often do not report any symptoms of Accommodative Insufficiency.
Accommodative Insufficiency in children has the potential of being misdiagnosed as ADHD/ADD or learning disability. Of note, it has also been found that Accommodation can be altered significantly by medications such as Adderall, Ritalin, Concerta and Dexedrine.
There are also several systemic findings associated with accommodative dysfunction. They can include neurasthenia (a condition characterized by general lassitude, irritability, lack of concentration, worry, and hypochondria), emotional factors, toxic conditions, dental caries or infection, as well as endocrine disturbances, anemia, and hypertension.