Wong D, Lois N:
Perfluorocarbons and Semifluorinated Alkanes
Seminars in Ophthalmology, 2000, 15, 1, 25-35

The article outlines the physical and chemical differences between perfluorocarbons and semifluorinated alkanes and discusses the associated opportunities for use as an intraoperative tamponade agent in ophthalmology. The efficacy as a tamponade liquid is determined by the density, contact angle, viscosity, surface and interfacial tension. The reduced density of F6H8 compared to conventional perfluorocarbons means its use as a long-term tamponade agent for inferior problematic cases is theoretically conceivable, although due to the increased emulsification rate caution is advised. As a temporary tamponade agent F6H8 can be used without any restrictions.

Meinert H, Roy T:
Semifluorinated alkanes – A new class of compounds with outstanding properties for use in ophthalmology
European Journal of Ophthalmology, 2000, 10, 3, 189-197

Semifluorinated alkanes are composed of a perfluorocarbon and a hydrocarbon component. They are physically, chemically and physiologically inert, colourless, laser stable liquids with a significantly reduced density ranging from 1.1 to 1.7 g/cm3 and a very low surface and interfacial tension. They are thus suitable tamponade agents for retinal manipulations. In addition semifluorinated alkanes are soluble in perfluorocarbons, hydrocarbons and silicone oils. This combination of properties makes semifluorinated alkanes an interesting candidate for a wide range of applications in ophthalmology.

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Schatz B, El-Shabrawi, Haas A, Langmann G:
Adverse side effects with Perfluorohexyloctane as a long-term tamponade agent in complicated vitreoretinal surgery
Retina, 2004, 24, 567-573

F6H8 was used as a long-term tamponade agent in 18 patients with inferior retinal damage over a period of two to 14 weeks, with the post-operative observation period being between three and 18 months. Long-term reattachment of the retina was achieved in 10 cases (56%). The side effects resulting from use of F6H8 include light sensitivity (2 patients), pain (2 patients), hypotension (2 patients), severe emulsification (1 patient), corneal damage (1 patient), formation of fibrous membranes (5 patients), posterior lens clouding (1 patient) and retinal scarring (1 patient). To reduce the number of side effects, F6H8 should only be retained in the eye for as short a period as possible when used as a long-term tamponade agent.

Langefeld S, Kirchhof B, Meinert H, Roy T, Aretz A, Schrage NF:
A new way of removing silicone oil from the surface of silicone intraocular lenses
Graefe´s Arch Clin Exp Ophthalmol, 1999, 237, 201-206

Intraocular lenses (Domilens) are moistened with small stained (Sudan IV as dye) silicone oil drops (AdatoSIL-OL 1000 or 5000) and then rinsed with F6H8. Small silicone oil droplets (50 to 100 µl) can be rinsed from the lens surface with a small quantity of F6H8 (800 µl). Larger drops are not completely removed even with 2 ml of rinsing solution (F6H8). Due to their differing viscosities, silicone oil traces of viscosity 1000 mPas can be removed more easily from the lens surface with F6H8 than traces of silicone oil 5000.

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Kobuch K, Menz DH, Hoerauf H, Dresp JH, Gabel VP:
New substances for intraocular tamponades: perfluorocarbon liquids, hydrofluorocarbon liquids and hydrofluorocarbon-oligomers in vitreoretinal surgery
2001, 239, 635-642

As well as F4H4 and oligomers composed of two to four linked F6H2 units, F6H6 and F6H8 are suggested as intraocular tamponade liquids. Due to the low viscosity for all semifluorinated alkanes significant emulsification developed within the first week which can lead to severe side effects. Oligomers composed of F6H2 units, which display a significantly increased viscosity of approximately 90 to 1000 mPas, were suggested as possible alternatives.

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