Abstract
Purpose:
Intraocular silicone oil impurities may cause intraocular inflammation, retinal toxicity and emulsification resulting in opacification of the optical media. However, clouding or color changing of silicone oil in the absence of emulsification have not been described before.
Methods:
Twelve patients who received 5000cs medical grade silicone oil developed opacification of the intraocular silicone oil tamponade without emulsification within few weeks after surgery. The medical charts and surgical notes of the respective patients were investigated in order to find out whether a common cause for the opaque oil could be determined. Moreover, a variety of physicochemical analyses were performed in order to reveal molecular differences in between different production lots of silicone oils.
Results:
Chart review revealed that all patients that presented with “dirty” intraocular silicone oil had received silicone oil from the same production lot from a single manufacturer. All other patients that also had silicone oil instillation from the same production lot were traced, informed and scheduled for silicone oil removal. No obvious retinal toxicity due to the impure oil could be observed. Unused vials from the respective lot and samples obtained from patients during silicone oil removal were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF), gel permeation chromatography (GPC), high performance liquid chromatography (HPLC) and thermogravimetric analysis (TGA). The first three methods all show the presence of what presumably is a small molecular weight compound in the reference silicone oil, but that is absent in the opaque lot. Surprisingly, TGA revealed that the opaque lot is more temperature stable than the reference oil that did not show opacification. As such it is hypothesized that the reference lot contains a stabilizing agent against coloration, but that has a negative influence on the thermal stability of the product.
Conclusions:
Opacification of intraocular silicone oil could be traced down to a specific production batch of one manufacturer.
Keywords: 764 vitreous substitutes •
762 vitreoretinal surgery •
697 retinal detachment