Photo Credit: Zarina Lukash
The following is a summary of “Dislocation force of scleral flange-fixated intraocular lens haptics,” published in the March 2024 issue of Ophthalmology by Pukl et al.
Researchers conducted a retrospective study to assess the dislocating forces concerning haptic material, flange size, and needle type.
They utilized 30 G (gauge) thin-wall and 27 G standard needles to create a 2 mm tangential scleral tunnel, paired with various PVDF (polyvinylidene fluoride) and PMMA (polymethylmethacrylate) haptics. Flanges were formed by heating 1 mm of the haptic end, employing forceps assistance for PMMA haptics and non-forceps assistance for PVDF. Using a tensiometer device, a dislocation force assessment was conducted on the non-preserved cadaver sclera.
The results showed that PVDF flanges took on a mushroom-like shape, while PMMA flanges exhibited a conical shape. For 30 G needle tunnels, the dislocation forces for PVDF and PMMA haptic flanges were 1.58 ± 0.68 N (n = 10) and 0.70 ± 0.14 N (n = 9) (P=0.003). The dislocation forces for 27 G needle tunnels for PVDF and PMMA haptic flanges were 0.31 ± 0.35 N (n = 3) and 0.0 N (n = 4). The flange size correlated with the dislocation force in experiments with 30 G needle tunnels (r = 0.92) when the flanges were larger than 384 micrometers.
Investigators concluded that PVDF haptics, with their mushroom-like shape, generated the highest resisting force against dislocation in 30G thin wall needle scleral tunnels, highlighting their advantage over PMMA’s conic shape, even with assisted flange creation.
Source: bmcophthalmol.biomedcentral.com/articles/10.1186/s12886-024-03369-x
