Tricks of the Trade: Fluorescein application techniques for the eye

2016-11-11T19:37:12+00:00

stain-fluoresceinApplication of fluorescein is a vital part of the workup of ocular complaints. Despite some studies showing questionable support, the typical cited clinical concern for stored fluorescein solutions is contimination with Pseudomonas and risk for iatrogenic infection with associated ulcer formation. 1–4 Subsequently, single dose sterile strips have become the standard agent stocked in most EDs. Many patients, especially children, can be apprehensive of the application of the physical strip directly to the eye, and are more comfortable with the concept of eye drops. In this post, we review multiple technique to create fluorescein solutions and additional tips for utilization that may be integrated into your practice, depending on the supplies available to you.

Strip-In-Syringe

This technique was first described in a guest post from Dr Ian Brown. The strip is placed directly into the syringe, and sterile saline is drawn in with the strip. The blunt filling needle is then removed, and the solution is ready for application.

Figure 1. Strip-In-Syringe Technique

Figure 1. Strip-In-Syringe Technique

Mix-In-Packaging

This technique, utilizing a respiratory saline ampule and the strip packaging, is nicely photographed and explained in our prior post by Dr. Sam Ko and Dr. Kimberly Chan.

Dab-and-Withdraw

Another technique contributed by ALiEM-AAEM Fellow Dr Matt Zuckerman creates a solution directly in the syringe or respiratory ampule of saline. If using a 10 cc flush, you will want to discard saline until 3 cc is remaining. Saline is expressed to create a droplet at the tip of the syringe/ampule, and the strip is dabbed directly to this droplet.  Aspirating brings the fluorescein solution back into the container. This will need to be repeated a few times to achieve appropriate concentration of fluorescein. Because the need for precise syringe-work, there is a potentially for small spills utilizing this technique, so plan accordingly.

Figure 2. Dab Technique. This can be performed with syringe or ampule of saline.

Figure 2. Dab Technique. This can be performed with syringe or ampule of saline.

Specimen Cup

This is a technique I frequently utilize in my department because of the supplies that are most readily available and some messy mishaps with the above dab-and-withdraw technique. Simply dispense 3 cc of sterile solution in a sterile specimen cup, mix the fluorescein directly into the solution, and then load into syringe. We did utilize a blunt filling needle in our example, but you may load directly into the syringe if you prefer. Left over solution in the cup can be used to explain the nature of the stain and also help motivate younger patients (“This will give you super glowing eyes!”).

Figure 3. Specimen Cup Technique

Figure 3. Specimen Cup Technique

Angiocath Dropper

Regardless of the technique used to create a syringe of solution, there can be some awkwardness with application. Unlike the saline ampule, the syringe has properties which make it behave unlike a typical eye dropper. Overcoming the static friction of the syringe plunger can cause a sudden stream of fluorescein solution that can be uncomfortable or surprising for patients. This can also potentially stain clothing and lessen patients overall trust and comfort in the exam setting. I have found that applying a 24G angiocath tip to the Luer-Lok syringe can help create more control applying the solution. The small droplet size has also helped me successfully stain children who were squinting, foregoing the need to pry eyelids open and cause additional discomfort and anxiety.

Figure 4. Angiocather tip assists delivery of fluorescein solution

Figure 4. Angiocather tip assists delivery of fluorescein solution

Happy Staining!

Top image credit

1.
Claoué C. Experimental contamination of Minims of fluorescein by Pseudomonas aeruginosa. Br J Ophthalmol. 1986;70(7):507-509. [PubMed]
2.
Duffner L, Pflugfelder S, Mandelbaum S, Childress L. Potential bacterial contamination in fluorescein-anesthetic solutions. Am J Ophthalmol. 1990;110(2):199-202. [PubMed]
3.
Rautenbach P, Wilson A, Gouws P. The reuse of opthalmic Minims: an unacceptable cross-infection risk? Eye (Lond). 2010;24(1):50-52. [PubMed]
4.
VAUGH D. The contamination of fluorescein solutions; with special reference to pseudomonas aeruginosa (bacillus pyocyaneus). Am J Ophthalmol. 1955;39(1):55-61. [PubMed]
Sam Shaikh, DO

Sam Shaikh, DO

Editor, 60-Second Soapbox series
Assistant Clinical Professor, Rocky Vista University
Clinical Instructor, University of Colorado School of Medicine
2014-15 ALiEM-CORD Social Media and Digital Scholarship Fellow
  • Amanda L. Fowler, PharmD

    Are there any alternatives to this diagnostic agent? We are experiencing significant supply issues with fluorescein strips due to manufacturer back order.

    • Oh my, a shortage/back order? I don’t know of any good alternative. Seems maybe a different manufacturer vendor is in order? Good luck!

  • I’ve had luck with gently pulling down the lower lid and tapping the wet test strip to the inner lower lid instead of the globe itself. When the patient blinks the fluorescein spreads where it should. In peds especially the sight of a piece of paper may be less threatening than a syringe. Great to have many options in your toolbox though.

    • The only issue with this technique is the risk of causing an abrasion itself if the child moves or you are not precise. You can hover the strip over the lower eyelid, drip the tetracaine or saline along it and let the fluorescing drip into the lower eyelid “cup.”

      Also, when doing this get the child to look up – this reduces the blink response. Distraction (everything from jingling keys to an iPad) will help. Also, enlist a holder!

  • Greg

    I like to use a saline bullet–squirt out 2/3 the saline, then squeeze two drops onto fluorescein strip and suck them back into the bullet; repeat. Shake and you have enough sterile solution for a few drops in both eyes.

  • Petra Dolman

    I’m a fan of the strip in the syringe. I used it often on my EM rotation and had an very skeptical attending, who a month later caused an abrasion with a strip themselves and then became a convert to this method. Its good to be a skeptic, but remember your learners can teach you as well 🙂 Great post!

  • Annaba

    How can you remove the flourescein from the eye quickly? a saline eyebwash sinse its water soluble ??

    • Indeed. Water or saline eyewash should do the trick. May take a few washings. Be aware that if you had a contact lens in, that is irreversibly stained.