Fluorescein pooling effect assists late lifting of LASIK flaps

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January 09, 2025

3 min read

A quick look at ChatGPT tells me that there have been few reports of “late lifting” after LASIK.

The best article is referenced, and the actual technique for late lifting is described, but the most difficult part is identifying the flap margin, and I will address that herein.

Putting my age to my advantage, I have slowly upped the period when I consider flap lifting over PRK. For the last decade, I have not met a flap I cannot identify and lift.

This apparently anomalous practice has been highlighted by my chief operating officer, Stephanie Cohen, who has an exceptionally long firsthand history in the LASIK world. “I have never heard or seen anyone lifting a flap after a decade,” she once told me. Obviously, my response was, “They weren’t Siepser!” The literature is on my side. A couple of decades ago, I started to use the “yellow” filter on our Haag-Streit slit lamps to help increase the contrast and visualize the flap edge. I noted that even with that trick, I would have some difficulty identifying the flap edge and would use an “indentation” method to delineate the flap edge. Applying indentation pressure with a Sinskey hook near the suspected flap edge would delineate the area of the edge with a small area of crinkling or folding over the flap edge.

Figure 1. An example of LASIK flap edge pooling. The arrow shows the area of pooling over the flap edge.

*Source: Steven B. Siepser, MD, FACS*

Over the last decade, I began to use fluorescein “pooling” to identify hard-to-see flaps. Now that I am finding the need to enhance LASIK that was done up to 25 years ago, I have leaned toward the use of fluorescein to help identify the flap edge in these late cases. Using a copious amount of fluorescein that “pools” on the eye and waiting a few moments for the “pooling effect” to occur over the flap edge have allowed me to lift these late flaps. This can also be supplemented with the indentation technique that further pools the fluorescein at the flap edge and better delineates the telltale “crinkle” in the epithelium at the flap margin.

Figure 2. This patient is 25 years out from LASIK and was a very high myope. It takes a little imagination, but once the surgeon starts to see the flap edge pooling, it becomes second nature. Sometimes that is all that is seen in older healed LASIK flaps. Here the pooling effect line is just lateral to the red line. It takes a moment to appreciate the fine outline of the flap edge, but in actual live slit lamp examination, it comes in and out of view. Once the surgeon is “locked on” to the image, it gets easier to visualize it even in the most transparent corneas.

Of course, ingrowth is more common, but this is not much more than an inconvenience. Once I see any ingrowth, I relift that area or the whole flap, which with a relift is more defined and has sharper borders. I can gently scrape off the offending cells with a Tooke knife and dry Merocel sponges on the stromal surface. I also use the same technique on the underside of the flap by draping it over a wet Merocel sponge and cleaning the underside meticulously. One of the key steps to decrease the incidence of post-lifted flap ingrowth is the use of a bandage –0.5 D Acuvue bandage contact lens (Johnson & Johnson) for 2 weeks, left in place and not changed unless there is proteinaceous buildup or intolerance. If the ingrowth recurs, I lift immediately and remove it. This attentive, repetitive technique eliminates any significant ingrowth successfully without fail.

Use of the yellow filter demonstrates the flat edge — Figure 3. Use of the yellow filter with a Haag-Streit straight slit lamp better demonstrates the flat edge and delineates it more clearly. We get maximum luminosity in the yellow area of the spectrum, and this increases the visibility of the flat edge. The blue lines define the outer corneal femtosecond astigmatic keratotomy and the inner blue line the edge of the LASIK flap.

This is so effective that I no longer PRK over even the oldest LASIK. We had a patient who had LASIK in Ecuador 23 years ago with an obvious Hansatome (no longer in production but formerly distributed by Bausch + Lomb) flap who we successfully treated. Recently, I lifted a flap for a patient who needed an enhancement after cataract surgery — a flap that had been done in Canada 25 years ago! Now we are looking forward to beating our record. We would like to help our colleagues better care for their patients by using a long and wonderful experience in refractive surgery to improve long-term outcomes for everyone.