Pneumatic retinopexy by evaporation of fluorocarbon liquids: in vitro and in vivo results.
OBJECTIVE
To develop an expanding gas tamponade allowing a controlled and complete filling of the vitreous cavity in the non-vitrectomized eye.


METHODS
Twenty-two different liquid fluorocarbon mixtures with a high vapour pressure were tested in an in vitro eye model and in rabbit eyes. The intraocular pressure (IOP), the anterior segment of the eye, the vitreous and the retina were inspected at each examination during a period of 2 weeks. The timepoint of maximal gas expansion and the period required for complete absorption of the gas bubble were recorded.


RESULTS
In vitro, admixtures of perfluorocarbons (PFCLs) and of semifluorinated alkanes (SFAs) with ether/alkanes generated limited temporary gas expansion but increased IOP. Admixtures of n-pentane in paraffin oil or silicone oil resulted in incomplete gas filling remaining for several days, with moderate IOP. In vivo, different clinical features and gas expansion were observed after the injection of PFCLs saturated with CO(2) or SF(6). Normal IOP was noted, but only with a transient and incomplete gas expansion and tamponade. For example, with n-pentane/n-hexane/perfluoromethylcyclopentane/perfluoromethyl-cyclohexane (1:1:1:1) a very rapid gas expansion was observed, followed by a raised IOP, a shallow anterior chamber, and finally rupture of the globe. The correlation between the in vitro and in vivo data was low.


CONCLUSIONS
Gas endotamponade based on evaporation of liquid fluorocarbons is possible, but a complete and reliable tamponade could not be achieved. The best results were demonstrated by admixtures with an overall density <1.00 g/cm(3), an inert carrier with high vapour pressure, and a highly volatile substance. Further detailed investigation into the factors influencing evaporation is required.
Mackiewicz
Jerzy
J
Department of Vitreoretinal Surgery, Center for Ophthalmology, University of Cologne, Cologne, Germany.
Mühling
Bastian
B
Hiebl
Wilfried
W
Meinert
Hasso
H
Kociok
Norbert
N
Joussen
Antonia M
AM
D000042:Absorption; D000818:Animals; D003720:Densitometry; D005466:Fluorocarbons / Q000008:administration & dosage* / Q000737:chemistry; D007267:Injections; D007429:Intraocular Pressure; D011817:Rabbits; D012163:Retinal Detachment / Q000601:surgery*; D012167:Retinal Perforations / Q000601:surgery*; D055548:Vapor Pressure; D014822:Vitreous Body; D014835:Volatilization
D005466:Fluorocarbons