Convergence insufficiency in children: tired eyes

Key takeaways

Convergence insufficiency means the eyes cannot easily turn inwards together for close work. Symptoms are tired eyes, headaches, blur, double vision or words that seem to move while reading.
A distance chart or school screening can miss it. The AAO says it is usually not found during school vision screenings, so tell the doctor that the trouble is at reading distance.
Treatment is for children with symptoms. Some people have the finding and no symptoms and do not need treatment (AAO, AAPOS).
In the 2008 CITT trial of 221 children, office-based therapy gave a successful or improved outcome in 73%, home pencil push-ups 43% and office placebo therapy 35%. Cochrane found no evidence that home options beat placebo.
In the CITT-ART trial of 310 children, therapy did not improve reading scores more than placebo (3.7 against 3.8 points). A reading problem needs its own assessment.

Convergence insufficiency means the two eyes cannot easily turn inwards together and hold there for close work, so a child's eyes tire, the print blurs or the words go double after a few minutes of reading. It is treatable. The trial evidence favours supervised, office-based exercises, and it does not support home pencil push-ups or the hope of better reading scores.

This page is for the child who reads fine for a while and then fades. It sets out what the problem is, why a routine screening can miss it, how it is found, and what each treatment showed in the trials. I explain the double vision side of the story in when a child says they see double, and the homework pattern in the homework headache that is actually an eye problem.

What is convergence insufficiency in a child?

It is a problem of teamwork at near. When we look at a page, both eyes turn inwards (converge) to aim at the same spot. The American Academy of Ophthalmology (AAO) says that with convergence insufficiency the eyes do not converge enough for near vision, so one or both may turn outward while reading. AAPOS, the paediatric ophthalmology society, describes the same thing as the eyes being unable to work together up close, typically with one eye drifting outward when looking at a word or object at near.

The AAO says anyone can develop it, but it is seen mainly in children and young adults, and that it is more likely when it runs in the family. Its cause is not fully known. It can also be acquired after an injury, brain disease or autoimmune disease affecting the eye muscles, which is why a sudden change deserves a proper look rather than exercises.

What does it look like when my child reads?

The typical picture is a child who starts reading comfortably and then tires. The AAO lists double vision, headaches, blurry vision while reading, squinting or closing one eye, words that seem to move or float on the page, and eyestrain or fatigue. AAPOS adds trouble concentrating on near work such as a computer or book. Not every child has every symptom.

The closed eye is worth noticing. Covering one eye probably helps because the two slightly different pictures no longer clash. A child who reads with a hand over one eye may be finding a workaround rather than being dramatic. Because the drift happens only up close, the eyes are straight when looking at the board or at the television.

Why did the school eye screening say my child's eyes were fine?

Because convergence insufficiency is usually not found during school vision screenings, according to the AAO. A screening typically checks how clearly each eye reads a chart at a distance, and the eyes of a child with this problem are straight and see clearly at that distance. The trouble starts at reading distance.

So a passed screening does not settle the question when the symptoms are all about close work. Tell the doctor that the trouble is at near, and the examination will include it. The same symptoms can also come from a need for glasses, for example in a long-sighted child who works hard to focus, which is why how two eyes work together is a useful read before the visit.

How do eye doctors find it, and does every child need treatment?

The doctor asks about symptoms and measures. AAPOS says convergence insufficiency is diagnosed by an ophthalmologist, optometrist or orthoptist from the history and from measuring convergence ability: the near point of convergence (how close a target can come before the eyes can no longer hold it together without double vision) and fusional vergence (how much prism the eyes can overcome before double vision appears). The doctor also checks for glasses, other eye movement problems and weak near focusing.

Treatment is needed only when there are symptoms. The AAO and AAPOS both say some people have the finding and no symptoms at all and do not need treatment, though they should be followed.

AAPOS also notes that a poor result in the room can reflect a child who is distracted, shy, over-excited or who did not understand the instructions, so the test may be repeated at another time. The reverse also happens: a child with good numbers but real symptoms at school may be offered a course of treatment and followed for improvement.

What treatment has trial evidence, and what did pencil push-ups show?

Office-based therapy with home reinforcement has the strongest trial evidence. In the Convergence Insufficiency Treatment Trial (CITT), published in Archives of Ophthalmology in 2008, 221 children aged 9 to 17 with symptomatic convergence insufficiency were randomly assigned to one of four treatments for 12 weeks. A successful or improved outcome was found in 73% of those given office-based vergence and accommodative therapy, 43% of those doing home pencil push-ups, 33% of those doing home computer therapy plus push-ups, and 35% of those given office-based placebo therapy.

A placebo group is the useful comparison, because a child who is being treated and watched often feels better. The 2020 Cochrane review (Scheiman and colleagues) pooled 12 trials with 1,289 participants, six of them in children.

It found high-certainty evidence that office-based therapy with home reinforcement raised the chance of a successful outcome (defined by normal convergence measurements plus a set amount of improvement) compared with home pencil push-ups (risk ratio 2.86), home computer therapy (1.96) and placebo (3.04). It found no evidence that either home-based option did better than placebo therapy. Some of the authors also led the CITT trials, which the review discloses.

A pencil on the dining table is therefore not what the trials support. AAPOS says on its glossary page that home treatment is often enough, but the Cochrane pooling of the CITT trials is the direct comparison. AAPOS also says a short course helps symptoms and long courses show no extra benefit.

Exercises are not for every child: the AAO says they are not recommended for all patients, and prism glasses and, rarely, surgery are other options. Eye exercises and vision therapy: what the evidence says covers where exercises do and do not work for other eye problems.

Will treating it improve my child's reading or school results?

Not on the evidence so far. The Attention and Reading Trial (CITT-ART, Optometry and Vision Science, 2019) randomised 310 children aged 9 to 14 with symptomatic convergence insufficiency, two-to-one, to 16 weeks of office-based therapy or placebo therapy. Reading comprehension improved by 3.7 standard score points in the therapy group and 3.8 in the placebo group, a difference that was not statistically significant, and no secondary reading measure differed either. The authors advise clinicians not to suggest that this treatment will improve reading test performance.

A companion CITT-ART report found the treatment did change the eyes: the near point of convergence improved by 10.4 cm with therapy and 6.2 cm with placebo. Yet the symptom score fell by a similar amount in both groups (11.8 and 10.4 points), so the authors cautioned against judging success on a symptom questionnaire alone. The AAO also notes that learning disabilities are not caused by convergence insufficiency. A child who is struggling to decode words needs a separate assessment, as reading difficulty is usually not an eye problem explains.

Does it come back, and what about glasses, prisms or a patch?

It can. The AAO says convergence insufficiency sometimes returns after successful treatment, and that restarting the exercises may help. In the one-year follow-up of CITT, 27 of the 32 followed children (84.4%) who were symptom-free after office-based therapy were still symptom-free a year later. The groups followed after the other treatments were small.

A patch is the wrong tool, because it makes a child use one eye at a time and the problem is the two eyes together; AAPOS says so. AAPOS also warns that base-in prism glasses may make stronger convergence and fewer symptoms less likely once the glasses come off. In children, the Cochrane review found one trial of base-in prism reading glasses and no evidence of a difference from placebo glasses. Ordinary glasses are a different matter and are prescribed when the measurements call for them.

Double vision that is new, sudden, constant or comes with a headache that keeps worsening, vomiting or a recent head injury is a separate situation and needs a doctor promptly. Otherwise, if reading regularly leaves your child tired, blurred or seeing double, book an eye examination and say that the trouble is at close work.

Book an eye examination soon, and do not wait for the next screening, if…

Your child sees double, or the words keep doubling, and it happens more than once.
Reading is regularly stopped by headache, tired or sore eyes, or a page that will not stay still.
Your child closes or covers one eye to read, or keeps losing their place after a few minutes.
Double vision starts suddenly, is there all the time, or follows a knock to the head. This needs a doctor promptly, not exercises.

Is this urgent? Today, this week or routine

Common questions

What is convergence insufficiency in children?

It is when the two eyes cannot easily turn inwards together and stay there for close work. Typically one eye drifts outward at near, while the eyes are straight for things far away (AAPOS). The AAO lists double vision, headaches, blurry vision, squinting or closing one eye, and words that seem to move while reading.

Why do my child's eyes get tired and blurry when reading but not at the board?

In convergence insufficiency the outward drift happens only when the eyes focus at near, so distance vision and the eyes' alignment look normal. The AAO says the problem is usually not found during school vision screenings. A full eye examination that tests near vision can find it.

Do pencil push-ups work for convergence insufficiency in children?

In the 2008 CITT trial, 43% of children doing home pencil push-ups had a successful or improved outcome, against 73% with office-based therapy and 35% with office placebo therapy. The 2020 Cochrane review found no evidence that home pencil push-ups did better than placebo therapy, and high-certainty evidence that office-based therapy did better than push-ups.

Will convergence insufficiency treatment improve my child's reading or school results?

The CITT-ART trial found it did not. In 310 children aged 9 to 14, reading comprehension rose 3.7 standard score points with therapy and 3.8 with placebo therapy, which was not a significant difference. Treatment is aimed at the symptoms of close work, not at reading performance.

Does every child with a poor convergence test need treatment?

No. The AAO and AAPOS say treatment is needed only when there are symptoms, and that a child without symptoms should be followed. AAPOS adds that a poor result can come from a child who is distracted, shy, over-excited or who did not understand the instructions, so the test may be repeated.

Can convergence insufficiency come back after treatment?

Yes. The AAO says it sometimes returns after successful treatment and that restarting exercises may help. In the one-year follow-up of CITT, 27 of 32 followed children (84.4%) who were symptom-free after office-based therapy were still symptom-free a year later.

Are glasses, prisms or an eye patch used to treat convergence insufficiency?

A patch is not a good option, because it makes a child use one eye at a time (AAPOS). Base-in prism glasses may make stronger convergence less likely once they are off (AAPOS), and the one children's trial in the Cochrane review found no difference from placebo reading glasses. Ordinary glasses are prescribed when the measurements call for them.

References

Archives of Ophthalmology · Randomized clinical trial of treatments for symptomatic convergence insufficiency in children (CITT Study Group, 2008) · pubmed.ncbi.nlm.nih.gov
Optometry and Vision Science · Effect of Vergence/Accommodative Therapy on Reading in Children with Convergence Insufficiency (CITT-ART, 2019) · pubmed.ncbi.nlm.nih.gov
Optometry and Vision Science · Treatment of Symptomatic Convergence Insufficiency in Children Enrolled in CITT-ART (2019) · pubmed.ncbi.nlm.nih.gov
Optometry and Vision Science · Long-term effectiveness of treatments for symptomatic convergence insufficiency in children (CITT Study Group, 2009) · pubmed.ncbi.nlm.nih.gov
Cochrane Database of Systematic Reviews · Interventions for convergence insufficiency: a network meta-analysis (Scheiman et al., 2020) · pubmed.ncbi.nlm.nih.gov
American Academy of Ophthalmology · Convergence Insufficiency · www.aao.org
AAPOS · Convergence Insufficiency (glossary) · aapos.org

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.

Eyes that tire, blur or go double when reading up close: convergence insufficiency in children