Solvent for removing silicone oil from intraocular lenses: experimental study comparing various biomaterials.

PURPOSE

To evaluate the effectiveness of a perfluorocarbon-perfluorohexyloctane (PFHO)-in removing silicone oil from different intraocular lenses (IOLs) and determine whether any removal technique enhances the removal of silicone oil.

METHODS

Six IOL materials were analyzed: standard poly(methyl methacrylate) (PMMA), heparin-surface-modified (HSM) PMMA, AcrySof, 2 polyHEMAs with different water contents, and a second-generation SLM-2 silicone. One or 2 microL of a highly viscous silicone oil (5700 cs) was applied to the center of each IOL optic. Perfluorohexyloctane (2 mL) was then used to remove the silicone oil by 1 of 3 techniques: immersion of the IOL in PFHO; irrigation of the silicone oil with a small, blunt cannula; mechanical wiping with a PFHO-saturated Merocel swab (used only when irrigation failed). Next, each IOL was examined by light and scanning electron microscopy. The expanse of silicone oil residue remaining on the IOLs was objectively quantified using an integrated computerized analysis system combined with energy-dispersive spectrometry.

RESULTS

After application of 1 microL silicone oil, immersion in PFHO did not remove silicone oil from any IOL material. Irrigation with PFHO removed the silicone oil from the HSM PMMA and polyHEMA IOLs, but oil remained on the other lens materials. Mechanical wiping was necessary to remove the oil from the PMMA, AcrySof, and silicone IOLs. Attempts to remove 2 microL of silicone oil produced similar results. Although mechanical wiping of the AcrySof IOL removed all silicone oil, a slight residue remained on the PMMA and silicone IOLs. The PFHO irrigation removed significantly more silicone oil from the HSM PMMA than the unmodified PMMA IOL (P =.001). More silicone oil was removed from polyHEMA IOLs than from the AcrySof or silicone IOLs (P =.05).

CONCLUSION

Although PFHO can remove silicone oil, it is of limited usefulness. The effectiveness of PFHO depends on the removal technique, IOL material, and amount of silicone oil present. Based on these results, we recommend PFHO irrigation followed by mechanical wiping with a PFHO-saturated swab.