Blurred or double vision with headache pain is very common. I have experienced this first hand during a headache. I had pain and tension around the left eye as well. It felt like someone with long finger nails was holding onto the back of my left eye. Our theory is that there is likely a communication issue between the upper neck and the muscles that control the eyes. There is a condition that is common where we can develop ocular or eye muscle trigger points causing abnormal tension and weakness. Trigger points or knots in our eye muscles will cause our visual system to work harder. Tension in the eye muscles can pull one or both eyes off of the midline. This is even more obvious when we try to focus on anything up close.
Your vision or eye muscle strain may be part of the reason for your headache pain. A difficulty focusing or looking down and reading is a common sign that you are having trouble bringing your eyes inward. Try this out! Hold a finger up in front of your nose and slowly bring it toward you. Keep your eyes focused as you go “cross eyed”. Doing this slowly and with some repetition should not be a problem. If this is difficult, causing you to close your eyes or look away, or causes pain, your eye muscles could be part of the problem. A common finding after a head injury, concussion or even whiplash is a nerve injury affecting the eye muscles of one or both eyes. This creates a continued strain and eye muscle pain. This can be treated with Physical Therapy and is not usually something that requires an optometry assessment. Most people with this problem have had a normal eye exam. The problem is not with the eye itself but the muscles and nerves that control the eye.
The problem is not with the eye itself but the muscles and nerves that control the eye.
Our theory is that this can occur with clenching and tension to the cranial sutures, most commonly the sphenoid bone. Tension and changes to motion of the upper neck including loss of proprioception or head and joint position sense can also affect the eye muscles.
Symptoms
Eye fatigue by the end of the day or with increased reading and activity
Pain around or behind your eye or eyes
Eye strain
Dizziness or feeling off
Depth perception issues, driving is more difficult and can be more stressful
Walking grocery aisles, especially the cereal aisle or large stores such as Costco.
Muscle trigger points in the eye muscles can be felt next to the edge of the orbit along the bone. We do not recommend pushing on the eye itself. Supporting next to the eye where the muscle attachments are and adding head motion can bias the cranial nerves of the eye. Increased pain with testing suggests a cranial nerve entrapment as part of the underlying problem.
The most common muscle involved is the superior oblique muscle of the eye. It is easier to feel this muscle as it goes through a sling on the inside of your eye. It is responsible for inward motion with the other eye muscles as well as rotating the eye inward.
A study conducted by Cesar Fernandez de la Peñas and colleagues on the palpation of the superior oblique muscles in people suffering with headaches showed that not only was pain greater to this ocular muscle but also more frequently painful the more severe or chronic the headache.
Eye muscle pain and muscle trigger points are common in tension headaches
Testing Double or Blurred Vision
There are tests that can be done to check to see if your eyes are working together. The most common is to check convergence and divergence. If you see one eye track different than the other than this means that there is a coordination problem and binocular vision is affected.
Convergence Testing
Things to look for during a convergence test
Eye switching back and forth. The brain is shutting off one eye at a time. This will cause you to lose your depth perception and requires your brain to work harder.
Eye drift of one eye. When this happens it is pretty obvious. One eye gives up and drifts outwards.
Increased inward eye motion. One eye is pulling in too much giving the perception that the other eye is weaker. In this case the eye that is turning in more has increased tension to the superior oblique.
Check divergence. Can the person follow the object out? Do they blink or close their eyes?
Symptoms of eye strain, dizziness and even headache can occur.
The Maddox Rod Test
Another test to confirm a difference in eye position is the Maddox Rod Test. This test uses a filter over one eye while shining a light at both. If both eyes are looking at the light then the red line the filter creates appears to be touching the light. If the light and line are separate then one or both eyes are ‘off’ or deviated.
These tests, when positive, confirm that there is a vision issue and further testing of the visual system and neck is recommended to determine the type of problem.
Treatments exist that can resolve ocular muscle trigger points. Understanding the type of problem is the first step.
You don’t know what you don’t know
(Or what you don’t test)
