To Develop a New Surgical Strategy for Removing Emulsified Droplets in the Eye to Reduce the Complications Associated the Use of Silicone Oil (SO)

Purpose: Emulsification is an inherent problem with the use of SO as a substitute for the vitreous; the emulsified droplets can cause postoperative complications, such as glaucoma, cataract and proliferative vitreoretinopathy. This study aims to reduce the complications associated with the emulsification of SO by developing a rinsing agent for removing any emulsified oil droplets formed. The current treatment approach of rinsing the eye cavity using balanced salt solution is found to be ineffective and there is currently no viable rinsing agent in the market. Methods: The proposed rinsing agent consists of hexamethyldisiloxane, the monomer of polydimethylsiloxane (PDMS) as the major component with a small portion of a silicone-based hydrophobic surfactant Dow Corning 749 fluid. Silicone oil 1300cSt was stained with BODIPY 493/503 and then dispersed in 4% Pluronic F68 in 1X phosphate buffer saline (PBS) to form an oil-in-water (O-W) emulsion. This emulsion was then added to and kept in an eye model chamber for 24 hours. The chamber was subsequently washed with the proposed rinsing agent or 1XPBS in the control experiment. The washout was collected and observed under an optical microscope. The chamber after rinsing was then filled with 1XPBS. After 24 hours, the number of emulsified oil droplets was quantified using a particle counter Coulter counter Multiziser 4. Results: In the in-vitro washing model, rinsing by the proposed washing agent led to a reduction of oil droplets; the amount of oil droplets remaining is only one-third of that after washing by 1XPBS. Moreover, an oil-in-water-in-oil (O-W-O) double emulsion was observed in the washout of the proposed rinsing agents. Fluorescence signals due to BODIPY were detected within the larger water droplets; this confirms that the initial SO droplets were encapsulated by an aqueous shell phase. The resultant O-W-O double emulsion could be washed away easily, while the remaining washing agent can be easily removed by evaporation. Conclusions: Emulsified SO droplets can be encapsulated within water droplets with the use of the proposed rinsing agent and the resultant O-W-O double emulsion can be easily washed away. Therefore, this proposed rinsing agent demonstrates an excellent potential in reducing the postoperative complications associated with emulsification after the removal of silicone oil