Abstract
Purpose: :
Emulsified silicone oil droplets from tamponade agents can cause secondary or emulsification glaucoma by blocking the trabecular meshwork. Visible signs of emulsification can be observed using slit lamp biomicrosopy or gonioscopy. However, the relevant droplet size causing glaucoma is far smaller and to date no method was available that could visualize or quantify these small droplets. It is also believed that emulsification resistance is one of the main criteria to assess the quality of silicone oil. This study aimed to quantify the size and number of oil droplets using particle size analysis.
Methods: :
Samples were prepared in 5ml round bottom long neck glass flasks with 0.8g of emulsifier and 7g of oil to exclude the liquid-air interface. Samples were agitated using a Heidolph Multi REAX mixer with an orbital stirring mechanism. The level of emulsification was assessed visibly. The aqueous phase was removed and passed through a 100µm flow cell and examined systematically under a microscope at 400X. Images were collected and image analysis performed.
Results: :
Under the microscope numerous oil droplets in the size range 1-20µm were observed in samples that were deemed to be free of droplets from visual inspection. These data will be compared with samples retrieved from patients following tamponade removal.
Conclusions: :
For the first time emulsification droplets of this size could be visualised. A technique to analyse emulsified oil droplets in a systematic and quantifiable way has been developed. This new technique will allow us to analyse different tamponade agents with respect to their specific emulsification resistance and will be a tool in the development of novel silicone oils with improved surface properties.
Keywords: retinal detachment • vitreous substitutes • vitreoretinal surgery