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Jun 29, 2025

Achieving optimal flange size for intrascleral haptic fixation - EyeWorld

by Liz Hillman Ever since Shin Yamane, MD, PhD, introduced flanged intrascleral haptic fixation with a double-needle technique (first describing it at the 2016 ASCRS Annual Meeting where he won the

by Liz Hillman

Ever since Shin Yamane, MD, PhD, introduced flanged intrascleral haptic fixation with a double-needle technique (first describing it at the 2016 ASCRS Annual Meeting where he won the Grand Prize at the ASCRS Film Festival and publishing it in 2017), surgeons have been refining and building upon this technique.

A recent paper published in the Journal of Cataract & Refractive Surgery adds to the body of research and improvements on the flanged method of intrascleral haptic fixation, with Kronschläger et al. describing how to “[attain] optimal flange size with 5-0 and 6-0 polypropylene sutures for scleral fixation.”

But first, a bit of background: How did we go from Dr. Yamane’s haptic fixation to fixation with polypropylene sutures? As Kronschläger et al. wrote in their paper, the use of sutures started with Canabrava et al. using 5-0 and 6-0 polypropylene sutures cauterized to IOL haptics for flanged fixation at the end of the suture, which is then buried within the sclera. From there, Dr. Canabrava has further refined his technique, and others have modified it as well.

Kronschläger et al. focused on flange size, writing that it’s “critical” for all of these techniques. “A too small flange may slip through the scleral tunnel and a too large flange may remain outside the scleral tunnel and later erode through the conjunctiva resulting in a risk for endophthalmitis,” they wrote.

The paper describes a technique to achieve optimal flange size with the sutures. “An optimal flange size meets two criteria: First, the flange is big enough not to slip through the tunnel. Second, it is small enough to be buried in the scleral tunnel to prevent eroding through the conjunctiva,” Kronschläger et al. wrote.

The authors created flanges in a laboratory setting using cautery while the polypropylene was held with forceps and not held with forceps. They found that while holding the suture with forceps created some flattening or microtraumas, forceps grip did not influence the shape or size of the flange.

Heating length, however, was influential in creating an optimal or suboptimal flange. The paper includes a table with the optimal heating time depending on the different fixation technique being used, polypropylene size, and needle thickness.

“In general, the optimal flange size for a 27-gauge needle tunnel requires 1 mm heating of a 5-0 polypropylene suture. The optimal flange size for a 30-gauge needle tunnel requires 1 mm heating of a 6-0 polypropylene suture. Alternatively, 2 mm heating of a 6-0 polypropylene suture creates an optimal flange for a 27-gauge needle tunnel,” Kronschläger et al. wrote.

The authors noted that the polypropylene sutures did not produce the same conic shape when heated that is usually produced with PMMA haptics. This conic shape, Kronschläger et al. continued, “might be more advantageous” at providing a better hold, but they stated that more research about the possible benefit of flange shape is needed.

The authors also noted that the research was a dry laboratory study and thus “[lacks] the ability to fully account for scleral properties and other variables.”

Dr. Canabrava said in a video that the “secret” for flange size is to cut the suture 1.2–1.5 mm from the base and create the flange with cautery.

Separately, Kronschläger et al. researched optimal flange size on haptics of different IOLs in a 2018 paper. The authors found that where the forceps held the haptic influenced flange shape on PMMA IOLs but not PVDF IOLs.

Read “Attaining optimal flange size with 5-0 and 6-0 polypropylene sutures for scleral fixation” in the Journal of Cataract & Refractive Surgery.