Combined Perfluorohexyloctane and Silicone Oil Tamponade as a Solution and Double Filling. Surface Properties in Simulated Retina

Abstract

Abstract: : Purpose: To explore the tamponade potential of combined use of silicone oil and perfluorohexyloctane(F₆H₈), a hydroperfluorocarbon liquid with excellent surface contact and to describe the surface properties of a) a solution of F₆H₈ in silicone oil with a density of 1.06 and a viscosity of 1100 cSt, and b) double filling with F₆H₈ and silicone oil. Methods: We constructed a transparent model eye chamber of PMMA that mimics the retina and allows visualisation of the surface interactions of different tamponade materials. F₆H₈ was coloured with a minimal amount of Sudan black. a) A square eye model was filled with protein solution. The solution of F₆H₈ in silicone oil (provided by Fluoron, Neu-Ulm, Germany) was injected. The volume of the tamponade agent was incrementally increased and photographed. The height and the width of the tamponade bubble were measured using a graphics program. The better the contact the wider the bubble and the lower the height. For comparison pure F₆H₈ and n-octane (a perfluorocarbon liquid) were investigated in the same manner. b) A cylindrical eye model was injected with different proportions of F₆H₈ inferiorly and silicone oil superiorly. The two bubbles were merged. The configuration of the mixed bubble was photographed. Results: a) The bubble width of the solution is significantly less than pure F₆H₈ or n-octane(multiple linear regression). The bubble height of the soultion is significantly higher than pure F₆H₈ or n-octane. The excellent surface contact of F₆H₈ is lost. b) With double filling there is no interface or a third compartment. The resulting globule forms a "floating egg", with poor support of the lateral compartments. The positioning of indents on the model increases contact at particular positions. Conclusion: a) The solution of F₆H₈ in silicone oil does not have the good contact properties of pure F₆H_8, but shows similar surface properties to pure silicone oil. b) Double filling with F₆H₈ and silicone oil reduces the retinal contact of both agents. Mixes of other proportions, or with other agents may provide better retinal contact. The model eye chamber is useful for further investigations of candidate agents.

Keywords: vitreous substitutes • vitreoretinal surgery • retinal detachment