Convergence Insufficiency/Vision Therapy
What is Convergence Insufficiency?
Convergence Insufficiency Therapy (CI) is a common binocular (two-eyed) vision disorder in which the eyes do not work at near easily. It is an eye teaming problem in which the eyes have a strong tendency to drift outward when reading or doing close work (exophoria at near). When you read or look at a close object, your eyes should turn inward together to focus (converge) so that they provide binocular vision and you see a single image. This usually happens easily, without thinking. If the eyes do drift out, the person is likely to have double vision. To prevent double vision, the individual exerts extra effort to make the eyes turn back in. This extra effort can lead to a number of frustrating symptoms which interfere with the ability to read and work comfortably at near.
What are the symptoms of Convergence Insufficiency?
A person who has convergence insufficiency may show and/or complain of the following while doing close work (i.e., reading, computer work, desk work, playing handheld video games, doing crafts, etc.):
• eyes feel tired or uncomfortable when reading or studying
• headaches when reading or studying
• blurred vision
• double vision when reading or studying
• see the words move, jump, swim, or appear to float on the page when reading or studying
• feel like your read slowly − lose concentration when reading or studying
• feel a “pulling’ feeling around your eyes with reading or studying
• words blurring or coming in and out of focus when reading or studying
• lose your place while reading or studying
• rereading the same line of words when reading
• squinting, rubbing, closing or covering an eye
• feel sleepy when reading or studying
• have trouble remembering what you have read
• problems with motion sickness and/or vertigo
Symptoms will be worsened by illness, lack of sleep, anxiety, and/or prolonged close work.
Some patients with convergence insufficiency are asymptomatic. This absence of symptoms may be due to suppression, avoidance of near visual tasks, high pain threshold, or occlusion of one eye when reading.
Suppression of vision in one eye causes loss of binocular (two-eyed) vision and depth perception. Poor binocular vision can have a negative impact on many areas of life, such as coordination, sports, judgment of distances, eye contact, motion sickness, etc. Consequently, a person with convergence insufficiency who is suppressing one eye can show some or all of the following symptom:
• trouble catching balls and other objections thrown through the air
• avoidance of tasks that require depth perception
• frequent mishaps due to misjudgment of physical distances
• avoidance of eye contact − poor posture while doing activities requiring near vision
• one shoulder noticeably higher
• frequent head tilt
• problems with motion sickness and/or vertigo
Avoidance of reading or other near tasks in a patient with convergence insufficiency who reports an absence of other symptoms is as important a reason for recommending therapy as any of the other symptoms associated with convergence insufficiency.
How Common is Convergence Insufficiency?
Convergence insufficiency has a reported prevalence among children and adults in the United States of 2.5 to 13%. Another way to look at it is 1 out of every 20 children suggesting that in a typical classroom 1-2 children may have this condition.
A relationship between convergence insufficiency and ADHD has recently been established. The symptoms of convergence insufficiency can make it difficult for a child to concentrate on extended reading and may overlap with those of ADHD. An apparent three-fold greater incidence of convergence insufficiency was seen among patients with ADHD when compared with the incidence of convergence insufficiency in the general US population. Children being evaluated for ADHD should also get a comprehensive eye examination as part of their evaluation.
What Causes Convergence Insufficiency?
Convergence insufficiency results from misalignment of the eyes when focusing on near objects. The exact cause isn’t known, but the misalignment involves the muscles that move the eye. Typically, one eye drifts outward when you’re focusing on a word or object at close range.
How Do You Detect Convergence Insufficiency?
Convergence (eye teaming) and accommodation (focusing) tests are the important diagnostic tools. A basic eye exam or screening with the 20/20 eye chart is not adequate for the detection of convergence insufficiency (and many other visual conditions). A person can pass the 20/20 test and still have convergence insufficiency. A comprehensive dilated vision evaluation by an eye doctor who tests binocular (two-eyed) vision and who can refer or provide for in-office vision therapy is recommended.
How Do You Treat Convergence Insufficiency?
Treatments for convergence insufficiency can be categorized as active or passive:
• Active treatment: a multi-site randomized clinical trial funded by the National Eye Institute has proven that the best treatment for convergence insufficiency is supervised vision therapy in a clinical office with home reinforcement (15 minutes of prescribed vision exercises done in the home five days per week). The scientific study showed that children responded quickly to this treatment protocol … 75% achieved either full correction of their vision or saw marked improvement within 12 weeks.
• Passive treatment: prismatic (prism) eyeglasses can be prescribed to decrease some of the symptoms. Although prism eye glasses can relieve symptoms, they are not a “cure” and the patient typically remains dependent on the prism lenses. In addition, adaptation problems can lead to the need for stronger prescriptions in the future. Scientific research as well as optometric and ophthalmological textbooks agree that the primary treatment of convergence insufficiency should be vision therapy.
How Does Vision Therapy Work In-Office?
Vision therapy is a type of physical therapy for the eyes and brain. It is a highly effective treatment for convergence insufficiency. Our office utilizes a 12 week in-office program. This consists of 12 in-office visits once a week. The sessions last approximately 30 minutes and homework assignments are given to be done during the rest of the week. Our office also utilizes a computerized vergence system program in conjunction with other in-office therapy techniques. The computer portion of therapy is fun and easy, a series of eye exercises are done at a computer. It’s just like playing a computer game. The computer automatically increases the challenge based on your improvement. The program will be tailored to your own personal binocular problems.
How Does Vision Therapy Work At-Home?
When patients are unable to come to our office for weekly therapy sessions we do offer an alternative. Our office utilizes a computer vergence system which can be done at home. At home computerized vision therapy is fun and easy. A series of eye exercises are done at a computer. It’s just like playing a computer game. The computer automatically increases the challenge based on your improvement. The program will be tailored to your own personal binocular problems. At-home vision therapy consists of 2 examinations, the convergence computer program and weekly monitoring via the computer. The first examination will be used to explain the program and how the at-home therapy is to be conducted. Once the computer program is completed another examination will be scheduled to discuss results. Patients performance is monitored weekly through the computer program. Patients will spend approximately 15 minutes per day, five days a week, doing different exercises assigned by the program. Typically it takes 12 weeks to complete the program. In the early stages of the exercises it is not uncommon to experience a decrease in performance from one session to another. This is because the patient has no developed the appropriate skills or endurance and their eyes tire quickly. As patients near the end of their assigned regimen, the exercises usually seem to become easier and easier, and their symptoms will subside.