Eye Alignment & Double Vision

When Your Eyes Aren’t Working Together

Your two eyes have to point at the same place, stay coordinated, and work with your brain to create one clear image.

When that system is not working comfortably, you may notice double vision, eye strain, headaches, difficulty reading, or symptoms that become worse when you are tired.

There are many possible reasons for these symptoms, and figuring out the cause is the first step toward deciding what to do next.

Double Vision Can Mean Different Things

Double vision—also called diplopia—is not a diagnosis by itself.

One of the first things your doctor will want to understand is whether the double image disappears when either eye is closed.

When double vision goes away after closing either eye, the two eyes may not be lining up together properly. When the doubling remains in one eye by itself, causes such as dry eye, astigmatism, cataracts, or other optical changes may be involved.

That distinction helps point the evaluation in the right direction.

It Does Not Always Look Like Two Images

Some eye-alignment problems are obvious. Others are much more subtle.

You might experience:

• Double vision that comes and goes

• Eye strain or tired eyes

• Headaches after reading or screen work

• Difficulty keeping your place while reading

• Words that seem to overlap or move

• Closing one eye to make a task more comfortable

• Difficulty judging depth or distance

• Symptoms that become more noticeable later in the day

These symptoms can have many different causes, so they do not automatically mean you have an eye-alignment problem. An evaluation can help determine whether the way your eyes are working together is contributing.

Why Can Eye Alignment Become a Problem?

Some people have a small tendency for their eyes to drift that their visual system normally compensates for without them ever noticing.

Sometimes that compensation becomes more difficult, especially during prolonged reading, computer work, fatigue, illness, or as visual demands change.

Other alignment problems may be related to strabismus, difficulty coordinating the eyes at near, changes in the nerves or muscles controlling eye movement, health conditions, injury, or other eye problems.

The important part is determining what is causing your symptoms rather than assuming every case is the same.

My Glasses Prescription Is Right. Why Are My Eyes Still Tired?

A glasses prescription helps bring an image into focus.

It does not necessarily tell us how comfortably your two eyes are coordinating with each other.

That is why someone can see clearly on the eye chart and still experience eye strain, intermittent double vision, or difficulty during prolonged visual tasks.

How Do We Evaluate Eye Alignment?

Your doctor may look at how clearly you see, how your eyes move, where they align at different distances, and how effectively they work together.

The evaluation may include measurements of the amount and direction of an alignment difference, along with an examination of your eye health and prescription.

What testing is needed depends on your symptoms and what your doctor finds.

Can Glasses or Prism Help?

For some patients, an updated glasses prescription may help address a contributing visual problem.

For certain alignment problems or double vision, prism may also be considered.

Prism changes where an image appears through the lens so the two images are easier for the visual system to bring together. It does not physically straighten the eyes or cure the condition causing the misalignment.

Whether prism is appropriate—and how much is needed—depends on the individual patient.

Sometimes the Right Answer Is a Referral

Not every cause of double vision is treated with glasses.

Depending on what your doctor finds, the next step might be monitoring, changing your prescription, using prism when appropriate, or referring you to another specialist for further evaluation or treatment.

Our job is to help determine what may be happening and guide you toward the appropriate next step.

New Double Vision Should Not Be Ignored

Double vision that has been present for years is very different from double vision that appears suddenly.

Seek prompt medical attention for new or sudden double vision, particularly when it occurs with symptoms such as weakness, numbness, trouble speaking or walking, a severe headache, a new drooping eyelid, a noticeably different pupil size, or other sudden neurological symptoms.

Some causes of sudden double vision require urgent medical evaluation.

Let’s Figure Out What Your Eyes Are Telling You

Double vision, eye strain, and difficulty keeping your eyes comfortable can be frustrating—especially when you are not sure why it is happening.

Our doctors can evaluate your vision, eye alignment, and eye health, explain what they find, and help determine the appropriate next step.