Abstract

SA.19.06

Pneumatic retinopexy by evaporation of Fluorocarbon-liquids: in vitro and in vivo results

Kociok N.¹, Mackiewicz J.^2,3, Hiebl W.⁴, Kim Y.-K.⁴, Günther G.⁴, Meinert H.⁴, Mühling B.⁴, Kirchhof B.², Joussen A. M.^1
1Department of Ophthalmology, Heinrich Heine University Duesseldorf, Germany, ²Department of Vitreoretinal Surgery, Center for Ophthalmology, University of Cologne, ³Department of Ophthalmology, Medical University of Lublin, Poland, ⁴Fluoron GmbH, Neu-Ulm, Germany

Objective: To develop a new expandable gas tamponade for a slow complete filling of the vitreous cavity.
Methods: Twenty five different liquid perfluorocarbon admixtures with gas were tested both in a glass eye and in rabbit eyes. The glass eye was filled with water and 20 – 40 µl of the respective gas component were injected with subsequent heating to 37 °C. Expansion of the gas mixture was observed for 3 hours. For the in vivo experiments, 20 µl of each substance was injected into the midvitreous (n=5 eyes per group). The eyes were monitored every hour for 4 h, then every 4 hours for 2-3 days, then twice daily for one week, daily for the next week. The intraocular pressure (IOP), the anterior segment of the eye, vitreous and retina were inspected at each examination. The time of maximum expansion and the period until complete absorption of the gas bubble were recorded.
Results: Several mixtures of perfluorocarbons and semifluorinated alkanes with ether/alkanes resulted in limited temporary gas expansion in vitro, associated with a large increase in IOP. Admixtures of Pentane in paraffin oil or silicone oil resulted in a complete gas filling remaining for several days with acceptable IOP. In vivo, different amounts of gas expansion were observed ranging from no expansion to positive reactions resulting in different levels of expansion. Normal IOP was maintained in these eyes, but only transient incomplete filling of the vitreous cavity with gas. A very rapid gas expansion associated with a rapid raise in IOP, shallow anterior chamber and finally rupture of the globe was observed, even in substances that were positively evaluated in the in vitro eye model. There was only limited correlation between the in vivo and in vitro data.
Conclusions: The study underscores the feasibility of endotamponade based on vaporization of liquid perfluorocarbons. Still a more detailed investigation on the factors influencing vaporization in vivo is required.

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