How to stain the cornea

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Indications

• To assess corneal epithelial damage, following trauma or in patients with ‘dry eye’ problems, using diagnostic drops, e.g., Fluorescein 2% or Rose Bengal 1%.

You will need

• Fluorescein 2% or Rose Bengal 1% – diagnostic drops or impregnated paper strips
• Normal saline drops
• Local anaesthetic drops
• Clean cotton wool or gauze swabs
• Torch or slit lamp (depending on availability/skill level) for illumination.

Preparation

• Explain to the patient that he/she will experience a cold stinging sensation when the drops are instilled.

Method

• Ask the patient to look up
• Instil the diagnostic Fluorescein or Rose Bengal drops or use the paper strips. When using the strips, moisten with a small amount of normal saline or anaesthetic drop, taking care not to touch the end of the strip (impregnated with the dye) with the dropper.

• Ask the patient to look up and gently touch the inside of the lower eyelid with the moistened strip, taking care not to touch the cornea
• Ask the patient to close the eye, gently wipe away any surplus fluid and wait about 30 seconds
• Using a torch or slit lamp with the appropriate colour light (blue light, if using Fluorescein, and white light, if using Rose Bengal), examine the corneal surface, note any staining and record in patient’s documentation.

Fluorescein stains green indicating corneal epithelial loss.

Rose Bengal stains red indicating dead tissue and mucus filaments.