What is convergence Insufficiency?

Convergence insufficiency (CI) is a binocular vision disorder, meaning that both eyes do not work together to produce one clear steady image – something that we take for granted when our eyes work properly. CI is defined as having a problem moving both eyes inward to focus on close objects such as print in a book.

For a person with CI this is an ordinary occurrence. The two eyes cannot converge to the same place sending conflicting messages to the brain.
Not Commonly Diagnosed – Why?
Convergence insufficiency is a condition that may not be discovered during a routine vision exam. It requires a comprehensive specialized series of tests.
A person may have this undetected vision problem and not even be aware of it, even though he/she may have had vision exams and glasses prescribed previously. Therefore a person with 20/20 eyesight can have CI.
Fortunately, convergence insufficiency is a condition that can be treated. Recent multi-center clinical trials, funded by the National Eye Institute, shows that convergence insufficiency can best be treated through a structure program of office based vision therapy.
Symptom Checklist
A person with convergence insufficiency (CI) may experience or demonstrate some of the following symptoms:
·         Covers or closes one eye
·         Day dreams
·         Dizziness                                                   
·         Motion sickness
·         Letters or lines run together
·         Words blur when reading
·         Double vision, when tired
·         Avoids close-up work
·         Rubs eyes
·         Eye strain and headache
·         Trouble concentrating, reading and remembering what was just read

Effects of Convergence Insufficiency

In reading, both eyes must turn inward (converge) and precisely align with each other. If the eyes have difficulty converging, a person will have to strain in order to comprehend the text. Studies have shown that comprehension is reduced when a person has to concentrate just to keep both eyes converged.

Additionally, a recent study at the University of California San Diego, reported that convergence insufficiency is three times more common in children with Attention Deficit Hyperactivity Disorder (ADHD) that in other children.

Convergence insufficiency causes difficulty in concentration while reading, which is one of the symptoms used to diagnose ADHD.

Studies on Convergence Insufficiency

The National Eye Institute, a branch of the National Institutes of Health (the medical research branch of the US Department of Health and Human Services) has been studying convergence insufficiency to determine the most effective course of treatment. Called the Convergence Insufficiency Treatment Trial (CITT), the study was conducted at medical research centers throughout the country, including the Mayo Clinic of Rochester, MN; the Bascom Palmer Eye Institute of Miami, FL; and the Ratner Children’s Eye Center at the San Diego School of Medicine.  The results of the study were published in the fall of 2008. 


The study concluded that office-based vision therapy in conjunction with daily exercises at home is the only effective treatment option for convergence insufficiency. Other treatment options--including home exercises called pencil pushups and computer software programs--were significantly less effective than office-based vision therapy. Vision therapy is an advanced optometric specialty that has been in existence for over 70 years. All optometrists learn about vision therapy in optometry school, but most optometrists who provide vision therapy services receive post graduate education in the field. 

This study is particularly important because it showed that office-based vision therapy can significantly reduce symptoms when a child reads. “We found decreases in the frequency and severity of symptoms that make schoolwork more difficult. Parents reported that they saw a significant decrease in their child having difficulty completing schoolwork at school or at home, appearing inattentive or easily distracted when completing schoolwork, and avoiding schoolwork. In addition, parents reported that they worried less about their child’s school performance,” reported Dr. Mitchell Scheiman, principal investigator of the study.

For an abstract on the CITT study from the National Eye Institute, click here.  

Below is the press release issued by the Mayo Clinic after the results of the clinical trial were released:

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