If your eyes are having a hard time working together, you might have convergence insufficiency (CI). This condition affects how the eyes move together, so rather than seeing one object, your eyes might focus on two different things individually.
CI can make reading, writing, and using the computer difficult. Estimates vary, but many studies report that about 2–8% of the population has CI, depending on age and screening methods used.
In this article, we’ll discuss everything you need to know about CI and how it’s treated.
How Does Convergence Insufficiency Happen?
Typically, your eyes should work in sync and turn slightly inward to lock onto a nearby object, giving you clear, single vision. But with CI, one or both eyes might drift outward instead.
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What Is Convergence Insufficiency?
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When you focus on something up close, small eye muscles (the medial rectus muscles) pull your eyes inward, helping them align on the target.
With CI, these muscles don’t coordinate properly, causing one or both eyes to drift slightly outward, resulting in misalignment.
Who is at Risk of Developing Convergence Insufficiency?
Some people develop CI with no apparent cause, but several factors increase your chances of having it:
- Long periods spent reading or using screens can worsen CI symptoms, especially in dual-monitor setups or virtual reality headsets
- Traumatic brain injuries (TBI) or concussions can cause persistent CI symptoms
- Neurological conditions like Parkinson’s disease, Alzheimer’s disease, and myasthenia gravis
Additionally, CI can be hereditary and is particularly common in children and young adults. Fortunately, CI can be managed with proper treatment and support.
What are the Symptoms of Convergence Insufficiency?
CI symptoms can make everyday tasks frustrating, especially when focusing up close. The most common symptoms of CI include:
- Eye strain (asthenopia)
- Headaches
- Blurred vision
- Double vision (diplopia)
- Difficulty concentrating
- Trouble focusing
- Short attention span
- Frequent loss of place while reading
- Words appearing to move, jump, or float on the page
- Tired or sore eyes
- Squinting, rubbing, or closing one eye
If you frequently experience these symptoms, see an eye doctor promptly.
How is Convergence Insufficiency Diagnosed?
Your eye doctor diagnoses CI primarily by observing your eye alignment during close-up tasks. They’ll check if your eyes drift outward more at near than at distance.
The tests used to diagnose CI are:
- Near point of convergence (NPC). Measures the closest point your eyes can comfortably focus without double vision.
- Positive fusional vergence (PFV). Evaluates how strongly your eyes can turn inward using prism lenses.
- Prism. Used to determine the amount of correction needed to align your vision and resolve double vision, indicating the severity of your CI
- Cover test (cover–uncover test). This test identifies eye misalignment and determines its direction.
How is Convergence Insufficiency Treated?
The good news is that CI is treatable, and several effective options exist. Treatment usually involves exercises or special lenses, and success depends on consistency and the type of therapy chosen.
These include:
- Vision therapy. Includes exercises you can do in-office with a specialist and ones you can do at home to build strength and coordination.
- Prism glasses. These special lenses shift the image, helping your eyes see a single image. They’re often a short-term solution for CI.
- Computer programs. These programs use interactive software to challenge your eyes’ focusing ability.
- Surgery. Typically reserved for severe cases of CI or related eye misalignment conditions like convergence insufficiency-related exotropia that have not responded to therapy.
At-Home Exercises
Small changes to your daily routine and at-home exercises can ease the discomfort associated with CI symptoms, especially when paired with structured therapy:
These include:
- Pencil pushups. Slowly move a pencil toward your nose while maintaining clear vision.
- Brock string exercises. Focusing on beads placed at various distances along a string.
- Dot-card exercises. Training your eyes by shifting your focus between printed dots.
- 20-20-20 rule. Take a 20-second break every 20 minutes by looking at something 20 feet away to relieve eye strain.
- Proper screen placement. Adjust your monitor so the top is at or slightly below eye level, approximately an arm’s length away.
- Manage lighting. Use consistent, even lighting to reduce glare, which can exacerbate symptoms.
- Hydrate and rest. Keeping your eyes hydrated and rested reduces general discomfort and fatigue.
- Taking breaks. Take short breaks from extended close-up work to move around, which helps maintain eye comfort.
Additionally, if you're a student or regularly perform detailed work, consider accommodations like sitting closer to the front of classrooms or using larger printed materials to ease strain and maintain visual comfort.
When Should You See A Doctor?
In rare instances, convergence issues may indicate a more serious underlying condition. Seek immediate professional care if you experience:
- Constant double vision (diplopia) that doesn't improve with rest.
- Sudden noticeable inward or outward eye turn.
- Dizziness or nausea.
- Neurological symptoms such as numbness, difficulty speaking, or loss of balance.
Additionally, CI can happen due to concussions or traumatic brain injuries (TBI) and can slow your recovery if left untreated. If you experience convergence symptoms after a head injury, prompt evaluation and treatment can significantly aid your overall recovery.
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