Convergence Insufficiency

Medically Reviewed by Whitney Seltman, OD on November 02, 2022
Written by Paul Frysh
3 min read

To see objects up close, your eyes must move together to point inward so you can focus on what you’re looking at. It’s an action called convergence. It lets your brain merge images from both eyes to process what you see. When your eyes can’t align in this way, you have convergence insufficiency (CI).

The condition means you might find it hard to focus your eyes when you read, play video games, or work on digital devices like smartphones and laptops. Unlike other vision problems, like nearsightedness or farsightedness, the shape of your eye is not the cause of convergence insufficiency. Instead, it’s due to trouble with the way your eyes work together.

When you try to focus on something close to your eyes, you may have:

You also might notice performance issues when you read, like:

  • Slow pace
  • Tiredness
  • Concentration problems
  • Trouble keeping your place

Other people might notice that one of your eyes turns outward when you read, or that you seem to squint or close one of your eyes.

In convergence insufficiency, movements of one eye don’t line up exactly with the movements of the other. The eye muscles in people with CI work normally. So the problem seems to be with the brain or the nerves that send signals to those muscles.

It’s not clear how or why it happens, though your genes may play a part. Also, some other conditions seem to make convergence insufficiency more likely:

Your eye doctor will ask about your symptoms and your health history and give you a full eye exam. This will help them rule out other causes of your symptoms, including nearsightedness, farsightedness, or eye muscle problems.

To diagnose convergence insufficiency, doctors do a few simple, painless tests to measure:

  • How well your nerves and muscles work to move your eyes inward toward your nose.
  • How close to your face you can focus before an eye starts to move outward. For people with CI, that point is typically more than 6 centimeters away.
  • How quickly you can switch your focus from distant objects to close ones.
  • How much your eyes drift outward while looking at things up close and far away.

Special exercises that your doctor might call “vision therapy” are the main treatment for convergence insufficiency. You’ll typically practice focusing on things at various distances. You might do these exercises with an eye specialist at their office, but you can also do them at home, sometimes with the help of a computer program.

The treatment generally works well. Most kids who did therapy with a specialist had normal or much better vision after 12 weeks of regular visits.

If your symptoms don’t improve with vision therapy, you may need special “prism glasses” to read or do other up-close activities.