How To Check Eyes For A Concussion: A Clinical Guide To Assessing Oculomotor Dysfunction

Detecting oculomotor dysfunction after a head impact requires systematic evaluation of pupil reactivity, smooth pursuit, and saccadic eye movements. While these field tests provide critical diagnostic indicators for potential traumatic brain injury, they are not a substitute for formal neurological evaluation, and any athlete or individual exhibiting signs of instability must be removed from play immediately.

Clinical Requirements and Foundational Assessment Tools

Before beginning an assessment for a concussion, you must establish a baseline or recognize that the absence of a baseline necessitates a comparison against standard physiological norms. Concussions frequently disrupt the brain's ability to coordinate ocular motor signals, leading to measurable deficits in visual tracking and pupillary regulation.

• Essential Diagnostic Equipment:
  
  
  • Penlight or high-lumen medical grade flashlight with a neutral white light output.
  • Target fixation object (a small sticker on a tongue depressor or a clinician's fingertip).
  • A quiet, well-lit environment to minimize peripheral visual distractions.
  • A stopwatch or digital timer for precise saccadic and recovery measurements.
• Mandatory Prerequisites:
  
  
  • Understanding the Glasgow Coma Scale (GCS) and the Standardized Assessment of Concussion (SAC).
  • Knowledge of cranial nerves II (optic) and III (oculomotor) functional pathways.
  • Assessment Duration: Allow approximately 5 to 7 minutes for a thorough oculomotor screening.

Procedural Workflow for Oculomotor Concussion Screening

Step 1: Evaluating Pupillary Light Reflexes

The pupillary reflex assesses the integrity of the autonomic nervous system's response to light. Start by observing the pupils in a static position. They should be equal in size, round, and reactive to light (the PERRL standard).

1. Ask the subject to look at a distant point to dilate the pupils slightly.
2. Bring the penlight in from the side of the face rather than directly in front of the eyes to avoid a defensive blink reflex.
3. Shine the light briefly into the right eye and observe the constriction of both the right (direct) and left (consensual) pupils.
4. Repeat the process for the left eye.
5. Check for anisocoria (unequal pupil size) or sluggishness (the pupil takes longer than one second to constrict).

Warning: A fixed, dilated pupil or a pupil that remains unresponsive to light in the presence of a head injury is a medical red flag indicating potential intracranial pressure or herniation. Seek emergency medical services immediately if this is observed.

Step 2: Assessing Smooth Pursuit Tracking

Smooth pursuit allows the eyes to follow a moving object steadily without jumping. Dysfunction here often presents as "cogwheeling," where the eye moves in small, jerky steps rather than a fluid arc.

1. Position yourself two feet from the subject.
2. Hold the target object at eye level, roughly 12 inches from the subject's nose.
3. Instruct the subject to keep their head perfectly still while following the object only with their eyes.
4. Move the object in a wide "H" pattern: move horizontally to the right, return to center, move vertically up, move vertically down, and repeat for the left side.
5. Watch for corrective saccades, where the eye loses the target and "jumps" to catch up, or symptoms of nausea/dizziness during the movement.

Step 3: Conducting Saccadic Eye Movement Tests

Saccades are rapid, jerky movements of the eye that shift focus from one point to another. In concussion cases, patients often demonstrate undershooting or overshooting (dysmetria) when shifting focus.

1. Place two targets (e.g., your two index fingers) approximately 10 inches apart at eye level.
2. Instruct the subject to shift their gaze back and forth between the targets on your command.
3. Perform 10 cycles of back-and-forth movement.
4. Observe for excessive head movement (the patient is trying to compensate for eye weakness) or an inability to land precisely on the target.

Step 4: Measuring Near Point of Convergence (NPC)

Convergence is the ability of the eyes to turn inward to maintain a single image of an object as it approaches the face. A break in convergence—where one eye drifts outward or the patient reports double vision—is a primary marker of post-concussion syndrome.

1. Hold a target at arm's length at eye level.
2. Slowly move the target toward the bridge of the subject’s nose.
3. Instruct the subject to maintain focus on the target until it becomes double or they experience strain.
4. Measure the distance from the nose where this "break" occurs.

Pro-Tip: A normal convergence range is within 5 centimeters of the nose. Any break point occurring beyond 6 to 10 centimeters is considered a positive clinical finding for concussion-related oculomotor deficit.

Technical Parameters of Oculomotor Dysfunction

The following table summarizes common visual metrics and their clinical significance in the context of a head trauma assessment.

Addressing Assessment Failures and Troubleshooting

Accurate assessment depends on isolating the eyes from external variables. Failure often stems from human error or environmental interference.

• Root Cause: Subject moving their head during testing.
  
  
  • Actionable Fix: Physically stabilize the subject's head by placing your hand gently on the back of their head or instruct them to press their head against a backrest.
• Root Cause: Inconsistent lighting conditions during pupillary check.
  
  
  • Actionable Fix: Conduct the assessment in a shaded area away from direct sunlight, which can cause ambient pupil constriction and mask subtle sluggishness.
• Root Cause: Subject experiences immediate vertigo/nausea.
  
  
  • Actionable Fix: Cease testing immediately. Do not push through symptoms, as this can exacerbate the underlying injury. Document the threshold at which the symptom began.
• Root Cause: Patient reports double vision only at the end of the day.
  
  
  • Actionable Fix: Re-test when the patient is fatigued. Concussion symptoms often manifest more severely after periods of cognitive or physical exertion.

Frequently Asked Questions

Can a concussion be diagnosed solely through eye exams?

No, an eye exam is an auxiliary assessment tool used to flag potential neurological issues. A definitive concussion diagnosis must be made by a licensed healthcare professional using a comprehensive clinical battery, including cognitive, balance, and symptom-based assessments.

How long do eye-related concussion symptoms last?

While visual symptoms often subside within 7 to 14 days, they can persist for months in cases of prolonged post-concussion syndrome. If eye tracking issues do not resolve, a referral to a neuro-optometrist or a specialist in vestibular therapy is required.

What is the difference between a saccade and smooth pursuit?

Smooth pursuit is the continuous, fluid movement of the eyes to track a moving object, whereas saccades are the rapid, point-to-point "flicks" of the eyes as they shift between stationary objects. Concussions impact the neural pathways for both systems differently.

Can I perform these tests on myself if I suspect a concussion?

Self-assessment is highly discouraged due to the potential for cognitive impairment affecting the ability to report symptoms accurately. If you suspect a concussion, seek a professional medical evaluation to ensure objectivity and safety.

Professional Medical Consultation Standards

If an individual displays any abnormal findings during these oculomotor checks, they must be referred to a sports medicine physician, neurologist, or specialized concussion clinic for formal diagnostic imaging and cognitive testing. Early intervention and strict adherence to a graduated return-to-play protocol are the gold standards for ensuring full neurological recovery following a traumatic brain injury.