title: Flow behavior of heavy silicone oil during eye movements.
abstract: OBJECTIVE
  Currently there are various heavy silicone oil (HSO) tamponade agents available for treating inferior retinal diseases. Most of these HSO agents are either homogeneous liquids or a mixture of two components. Variations in their emulsification rates in vivo have been reported. In this study, we investigated their flow behaviors during eye-like movements.
  
  
  METHODS
  A model eye chamber filled with various HSO agents was driven to perform eye-like movements. Five types of HSOs with different formulations together with 2 other tamponade agents were tested. Movements of various HSOs inside the chamber were captured by video recording and analyzed.
  
  
  RESULTS
  Oxane HD has a larger movement and higher velocity relative to the eye chamber than the less viscous Densiron 68. The behavior of Densiron 68 is similar to that of homogeneous HSO 1.07 and HSO 1.20. Both Oxane HD and 11% silica fluid show very different behaviors compared to the other HSO agents. In addition, 11% silica fluid shows behavior similar to that of F6H8, a low-viscosity tamponade agent.
  
  
  CONCLUSIONS
  The viscosity of HSO is not the sole parameter with which to determine the behavior of HSO during eye movements. Various HSOs that are manufactured by mixing different types of base SO and "heavy" additives show distinct flow behaviors. The solubility and stability of the heavy additives in the base SO alter its flow when subjected to eye movements, which may contribute to in vivo emulsification.
authors.affiliation: Department of Ophthalmology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong Department of Mechanical Engineering, Faculty of Engineering, University of Hong Kong, Hong Kong.
authors.forename: Yau Kei
authors.initials: YK
authors.lastname: Chan
authors.affiliation: Department of Eye and Vision Science, University of Liverpool, Institute of Ageing and Chronic Disease, Liverpool, United Kingdom.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Williams
authors.affiliation: Department of Ophthalmology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: David
authors.initials: D
authors.lastname: Wong
mesh_terms: D005133:Eye Movements / Q000502:physiology*; D005466:Fluorocarbons / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008954:Models, Biological; D012827:Silicone Oils / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005466:Fluorocarbons; D012827:Silicone Oils
keywords: emulsification; eye movements; heavy silicone oil; tamponade