Fluorescein in Ophthalmology

1. Dr Rajvin Samuel Fluorescein

2. ` Fluorescein is a synthetic   organic compound  available as a dark orange/red powder soluble in water and alcohol .

3. Synthesis: It can be prepared from  phthalic anhydride  and resorcinol  in the presence of  zinc chloride  via the  Friedel -Crafts reaction . Other name -   Resorcinolphthalein

4. Medical applications :  In  forensics  and serology to detect latent blood stains In Microbiology –To detect Leptospira strains under microscopy in Syphilis  Serology (FTA-ABS Test) In dentistry -  a dye applied to teeth to reveal plaque

5. Fluorescein sodium is used extensively as a diagnostic tool in the field of ophthalmology. It is applied topically in the form of a drop or it can be injected intravenously to produce a fluorescein angiogram. Topical fluorescein is useful in the diagnosis of corneal abrasions, corneal ulcers, herpetic corneal infections, and dry eye. Fluorescein angiography is used to diagnose and categorize  macular degeneration , diabetic retinopathy, inflammatory intraocular conditions, and intraocular tumors

6. In ophthalmology Ophthalmic research : Intraocular dynamic studies [ fluorometry ] Tear film drainage studies Penetration to anterior segment structures Fluorescein angiography [in acquired macular & Retinal vascular patholgies ] Staining techniques Test for dry eye Evaluation of tear drainage Applanation tonometry

7. Fluorescein angiography Photographic surveillance of passage of fluorescein through retinal and choroidal circulation Principle: A molecule is excited by light of certain wavelength to a higher energy level ,release photon then comes down to original state 2 ml of 25 % [0r] 5 ml of 10 % solution

8. 80 % protein bound and 20 % free into circulation PROCEDURE: White light from camera flash pass through blue excitation filter [488 nm ] stimulates Yellow – green barrier filter [533 nm] back into camera film A red free photograph is taken at 1 second interval 5-25 secs after injection onset

9. Phases : 1 . Choroidal 2. Arterial 3. Arteriovenous [capillary] 4. Venous 5. Late [elimination] Side effects of Fluorescein: Temporary yellowing , Orange yellow urine , Nausea,vomiting , Urticaria , Toxic neuritis ,Local tissue necrosis , Extravasation into skin , vasovagal reactions

10. Hypofluorescence : 1. Vascular filling defects 2.Blockage by haemorrhage RPE hypertrophy ,Hard - - exudates, Naevi ,…. Hyperfluorescence : Leakage Pooling staining Transmission [window defect]

11. Staining Techniques: Seidel’s test for Wound leak Corneal Staining for ulcers ,other epithelial defects

12. Test for dry eye Tear break up time To test for tear film stability , fluorescein dye is added to the eye and the  tear film  is observed under the slit lamp while the patient avoids blinking until tiny dry spots develop. The longer it takes, the more stable the tear film. A short tear break-up time is a sign of a poor tear film. Generally, >10 seconds is thought to be normal, 5 to 10 seconds, marginal, and <5 seconds low

13. Tests for lacrimal drainage Jones dye test : To distinguish between Anatomical and functional outflow problems Instil one drop of fluorescein into the conjunctival sac Put a cotton bud soaked in anaesthetic in the inferior meatus . If fluorescein is detected after five minutes, the system is patent (positive Primary Jones Test).

14. No fluorescein - Negative Primary Jones Test and the functional obstruction could be anywhere from the punctum to the Valve of Hasner . Next, wash the excess fluorescein from the conjunctival sac and syringe. Fluorescein detected, entered the sac - positive Secondary Jones Test and functional obstruction of the nasolacrimal duct. If No dye after syringing, negative Secondary Jones Test , because fluorescein not entered the sac and, thus, there is stenosis of the puncta or canalicular system - Anatomical obstruction.

15. Applanation tonometry  The intraocular pressure is inferred from the force required to flatten ( applanate ) a constant area of the cornea, as per the  Imbert-Fick law . 1.Anaesthetic & fluorescein instilled in conjuntival sac 2.With Cobalt blue filter,brightest illumination and prism advanced until touches apex of cornea 3.A pattern of 2 semicircles one above ,other below the horizontal midline

16. 4. Dial is rotated to align inner margins of semicircles to just touch each other 5.Reading on dial multiplied by 10 = Intraocular pressure

17. THANK YOU