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Ocular diagnostic preparations

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.

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Fluorescein sodium1


  • Use - tear film assessment, identification of corneal epithelial defects/corneal disease and perforation (Seidel test).

  • Action - absorbs light in the blue wavelength and emits green fluorescence.

  • Administration - a single drop is sufficient.

  • Additional information - remember to warn patients that their eye will look yellow but that this readily wears off. They may also find that handkerchiefs stain yellow for several hours after they blow their nose. It stains contact lenses.

Seidel test to detect a wound leak:

  • Apply concentrated fluorescein (eg, 2% solution or directly from a moistened fluorescein strip) over the suspect area of the anaesthetised cornea, whilst observing the site with a slit lamp.

  • If there is a leak, the fluorescein dye appears as a bright green fluid oozing from the orange dye concentrate.


  • Use - in eye units to perform fundus angiography.

  • Administration - intravenous: it remains largely intravascular and circulates in the blood stream. Patients are monitored for allergic reactions during and after the procedure.

  • Contra-indications - renal impairment and allergy to fluorescein.

  • Side-effects2 - discolouration of the skin (yellow tinge) and urine, vomiting, itching, sneezing, vasovagal syncope, allergic reactions including anaphylaxis (1 in 1,900: severe, 1 in 220,000: fatal).

Indocyanine green

  • Use - retinal angiography. Provides a better visualisation of the choroidal (rather than retinal) vasculature. In addition to visualising choroidal neovascularisation, it may also be helpful in assessment of inflammatory disease and choroidal tumours.

  • Administration - intravenous: remains largely intravascular.

  • Contra-indications - pregnancy, renal impairment, iodine allergy.

  • Side-effects - nausea and vomiting, sneezing and pruritus, staining of stool, vasovagal syncope and severe anaphylaxis (1 in 1,900).

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Rose Bengal 1%

  • Use - detection of corneal and conjunctival damage (desiccation or devitalised tissue, eg, good for diagnosis of keratoconjunctivitis sicca).

  • Action - stains damaged conjunctival and corneal cells.

  • Additional information - this should only be administered after applying topical anaesthetic, as it stings and may cause local irritation on application; advise patients of temporary coloured staining of the eye. The dye needs to be washed out afterwards.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • Next review due: 19 Sept 2028
  • 21 Sept 2023 | Latest version

    Last updated by

    Dr Pippa Vincent, MRCGP

    Peer reviewed by

    Dr Doug McKechnie, MRCGP
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