Article Highlights

• Convergence insufficiency (CI) is the primary cause of blurred vision, eyestrain, double vision, and headaches.
• Due to recent research, it is a familiar near vision issue that is beginning to gain recognition in the public eye.
• CI disorder hinders an individual’s ability to see, learn, read, and work at close (near) distances.
• Historically, convergence insufficiency has been undetected as a result of testing not being included in school screenings, basic eye exams, and pediatrician’s eye tests.
• It is possible for an individual to pass a 20/20 eye chart assessment and still have CI.
• CI treatments vary from prism lenses (considered a passive treatment) to vision therapy in the office (considered an active treatment).
• National Eye Institute research has shown that vision therapy in the office is the most effective form of treatment for convergence insufficiency disorder.
• Pencil pushups are the most frequent prescribed treatment, though scientific research shows that it may be ineffective.
• Eye surgery is hardly ever recommended.
• Though there are some clinical results that show CI is able to be treated at all ages, current research suggests that CI treatment should only be performed on children and young adults.

What Is Convergence Insufficiency?

Convergence insufficiency is a common two-eyed (binocular) vision disorder that keeps the eyes from properly working at close distances. It is an eye teaming problem where the eyes tend to float outward when performing close work, such as reading. In the event that the eyes do float outward, it is likely for the individual to have double vision.

To help prevent the possibility of double vision, one must exert additional effort in order to cause the eyes converge, or turn back in. This additional effort can result in several frustrating symptoms that may hinder the ability to work at ease at close distances or read.

What Are Some of the Symptoms Associated with Convergence Insufficiency?

An individual who has CI may complaint of or show any of the following while performing close work, such as reading, deskwork, computer work, crafts, handheld video games, etc.:

• Eyestrain (particularly when reading)
• Inability to concentrate
• Headaches
• Double vision
• Blurred vision
• Rubbing, squinting, closing, or covering eyes
• Recurrent loss of place
• Short attention span
• Drowsiness during the activity
• Difficulty remembering what was read
• Trouble with vertigo and/or motion sickness
• Words seem to jump, move, float, or swim

It isn’t at all uncommon for an individual with CI to close or cover one eye when he or she is reading in order to alleviate the blurred or double vision. These symptoms can often exacerbate as a result of lack of sleep, illness, anxiety, or prolonged near work.

Many individuals who test positive for CI may not even complain of any of the aforementioned symptoms, including double vision, since vision in one of their eyes has completely shut down. That is to say, while both eyes are healthy, open, and capable of seeing, the individual’s brain ignores the one eye in an effort to avoid double vision. This is known as suppression, a neurologically active process.

Vision suppression in one eye can result in the loss of depth perception as well as two-eyed (binocular) vision. Reduced two-eyed vision can have a negative impact on multiple aspects of life, including sports, coordination, eye contact, distance judgment, motion sickness, and more. As a result, an individual with CI who is suppressing vision in one eye may exhibit some of the following symptoms:

• Averting eye contact
• Frequent head tilt
• Poor posture during activities that require close vision
• One shoulder noticeably higher
• Problems with vertigo and/or motion sickness
• Difficulty catching balls/other objects that are thrown into the air
• Dodging depth perception-related tasks such as games that involve smaller balls that travel through the air, hand-eye coordination, handicrafts, etc.
• Regular mishaps as a result of ill-judged physical distances (especially within 20 feet of the individual’s body) such as:
  • Frequent knocking over or spilling of objects
  • Stumbles and trips on uneven surfaces, curbs, stairs, etc.
  • Bumping into furniture, doors, and other types of stationary objects
  • Car parking and sports accidents

In some instances, CI can result in an outward eye turn that reoccurs periodically if it is left untreated, which is known as intermittent exotropia.

How Common Is CI Disorder?

There are between 2.5 and 13 percent of U.S. children and adults who have convergence insufficiency.

How Is Convergence Insufficiency Detected and Diagnosed?

Convergence, or eye teaming, and accommodation, or focusing, examinations are crucial during the diagnostic stage. It is not adequate to simply have a standard eye screening or exam with the routine 20/20 eye chart. It is entirely possible for an individual to pass the 20/20 eye chart assessment and still have CI. In order for CI to be detected, a professional eye doctor must perform a comprehensive vision assessment that tests binocular vision and potentially refer or offer in-office vision therapy.

CI disorder is often left undetected in children of school age due to the fact that adequate testing is not performed in pediatrician’s offices, school vision screenings, or standard eye exams in many eye doctors’ offices.

The good news is that CI often responds well to the right treatment, but the bad news is that many individuals aren’t getting the necessary treatment early on due to the lack of testing. Children, young adults, and adults who are left undiagnosed and untreated often avoid reading and near work or utilize strategies that combat the symptoms that they’re experiencing—like using a finger or ruler to keep their place while reading, taking regular breaks, etc.).

How Is Convergence Insufficiency Treated?

Ultimately, there are two kinds of treatment for CI disorder: active and passive treatment.

• Active Treatment – A clinical trial that the National Eye Institute funded has shown that the ideal treatment for CI is supervised vision therapy in the office with home support. This consists of 15 minutes of vision exercises within the home five out of seven days a week. The study showed that the participants responded promptly to this particular method of treatment with 75 percent of them achieving full correction or significant improvements within just 12 weeks.
• Passive Treatment – To help reduce some of the symptoms that are being experienced, individuals are being prescribed prism glasses. While these glasses can help to relieve symptoms, they’re in no way a cure for the problem. As a result, the individual often will remain dependent on the lenses. Moreover, adaptation issues can often lead to stronger prescriptions being needed down the road. Research as well as ophthalmological and optometric textbooks concur that the best and most effective treatment for CI is in-office vision therapy.
• Pencil Pushups – Though there was a survey of optometrists and ophthalmologists conducted in 2002 that showed that pencil pushups performed in the home was a common treatment for CI, scientific research doesn’t support this particular treatment. In fact, studies that have been performed suggest that this method of treatment is not effective at eliminating CI symptoms.
• Surgical Care – Before making the decision to undergo eye muscle surgery, it is important that all other options have been exhausted and they have failed, at which point one should then still proceed with caution.

For more information about convergence insufficiency, contact the experts here at Performance Vision.