F4H5: a novel substance for the removal of silicone oil from intraocular lenses

Aim Adherent silicone oil on intraocular lenses (IOLs) following retinal detachment surgery induces large and irregular refractive errors and multiple images, and gives rise to glare, distorted and often poor vision. Its removal remains challenging, often requiring mechanical wiping or explantation. F4H5 is a new semifluorinated alkane into which silicone oil is readily soluble. The aim is to establish the effectiveness of F4H5 in removing silicone oil from three different types of IOL in vitro. Method Silicone lenses (Tecnis ZM900, Advanced Medical Optics, Inc.), hydrophobic acrylic lenses (MA60, Alcon Laboratories, Inc.) and PMMA lenses (Ocular Vision, Inc) were first immersed in phosphate-buffered saline, second in silicone oil, then in F4H5 (Fluoron GmbH) for 10 min and lastly vigorously agitated in F4H5 for 1 min. They were weighed at each stage using scales accurate to 0.0001 g to measure the weight of the adherent oil. Dynamic contact angle (DCA) analysis was used to assess their surface properties. Results Immersion in F4H5 alone removed 96.1% (+/- 1.23) by weight of silicone oil from the hydrophobic acrylic lenses, 91.4% (+/- 1.58) from the silicone and 95.6% (+/- 1.44) from the PMMA IOLs. Immersion combined with 1 min of agitation increased the removal to 98.8% (+/- 0.46) from the acrylic IOLs, to 93.7% (+/- 0.48) from the silicone IOLs and to 100% (within 60.0001 g) from every PMMA IOL. After treatment with F4H5, all IOL were optically clear. DCA hysteresis curves remained permanently altered. All measurements were highly reproducible. Conclusion F4H5 was highly effective at removing the bulk of the silicone oil from all three groups of IOL. The DCA measurements suggested that their surface properties were permanently modified.