Ocular motility is a high-yield station in the FRCOphth Part 2 Oral Examination and is commonly tested during OSCEs and clinical assessments. This seemingly straightforward task can reveal critical neuro-ophthalmic and strabismic clues — but only if approached in a structured and complete manner.
In this blog, I’ll walk you through a stepwise guide to examining eye movements confidently and systematically. This is not only essential for your exams but also for day-to-day clinical practice in ophthalmology.
🔍 What is the Examiner Looking For?
“Examine the eye movements of this patient.”
You may be given this simple command. What you do next must be methodical, focused, and complete — covering ocular alignment, extraocular movements, diplopia assessment, and saccades/convergence.
✅ Step-by-Step Ocular Motility Examination
🔹 1. Introduce Yourself & Observe
- Greet the patient and explain the test clearly.
- Ask: “Would you like me to begin with a cover test?” (Some examiners expect this.)
- Look for:
- Abnormal head posture
- Obvious strabismus
- Ptosis or eyelid asymmetry
🔹 2. Check for Manifest Strabismus – Light Reflex (Hirschberg Test)
- Shine a torchlight from about ½ metre directly at both eyes.
- Observe the corneal light reflex position to identify any tropia (constant misalignment).
🔹 3. Test the Nine Cardinal Positions of Gaze
- Ask the patient to follow your finger or penlight held at ½ metre.
- Move it slowly in an “H” or “X” pattern, covering all 9 positions:
- Primary
- Up-right / Up / Up-left
- Right / Left
- Down-right / Down / Down-left
- Hold each position for at least 5 seconds and observe for:
- Restriction
- Overaction or underaction
- Nystagmus
🚫 Avoid extreme gaze — it’s uncomfortable and can cause physiological nystagmus.
🔹 4. Ask for Diplopia
If a deviation is observed, ask:
“Do you see double?”
💡 Diplopia Rules You Must Know:
- Separation is maximal in the direction of the weak muscle’s action.
- The false image is produced by the affected eye and appears further in the direction the weak muscle moves the eye.
🧠 Example:
In a right 6th nerve palsy:
- Maximal diplopia in right gaze
- False image is seen further to the right and disappears when the right eye is covered
🔹 5. Check Saccadic Eye Movements
Often forgotten in exams!
- Hold two targets (your fingers or pen caps) apart — first horizontally, then vertically.
- Ask the patient to quickly shift gaze between them.
This is especially useful in identifying:
- Internuclear Ophthalmoplegia (INO)
- Subtle nerve palsies or recovering cases
🔹 6. Test Convergence
- Move a target slowly from ½ metre to the nose.
- Ask the patient to follow it and report any doubling or blurring.
✔️ Normal convergence near point is within 10 cm.
💡 Pro Tips for OSCE Success:
- Always comment aloud on what you observe (“There is underaction of right lateral rectus…”).
- Do not forget saccades and convergence, even if the case seems straightforward.
- Be ready to differentiate convergence insufficiency from accommodative insufficiency.
📌 Summary Checklist
| 1 | Introduce, inspect head posture/ptosis |
| 2 | Light reflex (Hirschberg) |
| 3 | 9 cardinal positions of gaze |
| 4 | Ask for diplopia and interpret |
| 5 | Perform saccades (H & V) |
| 6 | Check convergence |
🎯 Final Word
Even if the OSCE case doesn’t look complicated, don’t skip steps. A thorough and confident ocular motility exam can uncover subtle signs of 3rd, 4th, or 6th nerve palsy, thyroid eye disease, INO, or strabismus.
Stay systematic. Stay sharp.