How to make fluorescein strips

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Fluorescein strips are an essential diagnostic tool in eye care. They are useful for performing a number of procedures, such as measuring intraocular pressure, assessing dry eye and detecting corneal abrasions. Unfortunately, this basic item is not commonly available in many resource-limited settings. Here we describe how we make fluorescein strips at Mbarara University and Regional Referral Hospital Eye Centre.

What you will need

• Sterile filter paper (e.g., Whatman no. 1)
• A sterile bowl, such as a kidney dish
• Fluorescein sodium powder (20 g)
• Distilled sterile water (100 ml)
• A pair of scissors
• Empty injectable vials or any other small, sealed containers
• A sterile surface
• Sterile gloves, mask and apron.

Procedure

• Assemble all the materials on a clean tray
• Put on sterile gloves, mask and apron
• Prepare a 20% fluorescein solution by dissolving 20 g of fluorescein sodium powder in 100 ml distilled, sterile water
• Cut the filter paper into rectangles of approximately 5 cm wide and 8–10 cm long
• Pour a small amount of fluorescein solution into the bowl. Be careful not to spill, as fluorescein leaves stains
• Dip the long edge of the filter paper in the fluorescein solution and immediately remove it, as the solution spreads very quickly through the paper (Figure 1)
• Place the dipped filter papers onto a sterile surface to dry
• Once they are dry, use a pair of scissors to cut the paper into strips, with the dipped edge at one end (Figure 2)
• Store the strips in a sterile, sealed container (Figure 3).