AIM OSCE / OSPE • MBBS • 4th Year • Eye
Station 11 — Topical Anaesthesia, Fluorescein Staining and Corneal Assessment
Rapid Revision • Practical Skills • Viva
🎯 Candidate Task
Demonstrate the appropriate use of topical ocular anaesthesia and fluorescein staining, then examine the cornea and identify any superficial abnormality presented. Explain the purpose of corneal scraping when corneal infection is suspected.
⚡ Model Station Answer
- I would explain the procedure, obtain consent and check for relevant allergy before instilling topical ocular anaesthetic safely.
- I would apply fluorescein to the lower conjunctival fornix without touching the cornea.
- I would examine the cornea under magnification using cobalt-blue illumination.
- Areas of epithelial loss stain bright green; I would describe the site, size and pattern and look for a superficial foreign body.
- Corneal scraping in suspected microbial keratitis obtains material for microscopy and culture to identify the organism and guide antimicrobial treatment.
🔎 How to Perform / Approach
1
Prepare. Perform hand hygiene, introduce yourself, confirm the patient and explain the examination.
2
Position safely. Seat the patient comfortably at the slit lamp or appropriate examination device and obtain consent.
3
Instil topical anaesthetic. Ask the patient to look upward, gently lower the lower lid and place the drop into the lower fornix without allowing the bottle tip to touch the eye or lashes.
4
Apply fluorescein. Moisten a fluorescein strip if required and gently touch it to the lower conjunctival fornix, avoiding direct contact with the cornea.
5
Examine with blue light. Ask the patient to blink, then systematically inspect the corneal surface using cobalt-blue illumination and magnification.
6
State the finding. Identify any bright-green epithelial defect and describe its location, size and pattern; inspect for a visible superficial foreign body.
7
Complete. Thank the patient, dispose of used material safely and state that suspected infectious corneal ulceration may require corneal scraping for microbiological investigation.
Exam point: Never rub the fluorescein strip directly across the cornea. Vertical linear staining should prompt consideration of a foreign body beneath the upper eyelid.
🖼️ Visual Learning
VISUAL 1
Topical Anaesthesia, Fluorescein Staining and Corneal Examination
🎥 Practical Demonstration
Anterior Segment Eye Examination — Geeky Medics
Demonstrates practical anterior-segment examination, fluorescein application and examination using blue illumination.
Demonstrates practical anterior-segment examination, fluorescein application and examination using blue illumination.
📝 Important Viva Questions
1. Why is topical ocular anaesthetic used in this station?
Answer: It reduces ocular surface discomfort and facilitates careful examination in a painful eye.
2. Where should a fluorescein strip be applied?
Answer: It should be gently applied to the lower conjunctival fornix rather than rubbed directly on the cornea.
3. What does bright green fluorescein staining of the cornea indicate?
Answer: It indicates a defect in the corneal epithelium, such as an abrasion or ulcerated epithelial surface.
4. What may vertical linear fluorescein staining suggest?
Answer: It may suggest a foreign body trapped beneath the upper eyelid repeatedly scratching the cornea.
5. Why is corneal scraping performed in suspected corneal infection?
Answer: It provides material for microbiological examination and culture so the infecting organism can be identified and antimicrobial therapy appropriately guided.