97th DOG Annual Meeting 1999



M. Winter1, K. Kobuch2, D.-H. Menz3, H. M. Hoerauf4, C. Winter5, V.-P. Gabel2

Per-fluormethylcyclohexan (FMCH) may serve as a lipophilic wash-out-solution for perfluorocarbon liquids (PFCL). The efficiency of this new method was tested in vitro and the ocular tolerability was determined in vivo.

Material and methods: (I) Eyes from pigs without anterior segment and vitreous body were filled with perfluorodecalin, perfluorooctane or perfluoroperhydrophen-an-threne. These PFCL were macroscopically removed. The retina was rinsed with FMCH. Then aspiration of FMCH was performed. The retained PFCL and FMCH were quantified by gaschromatography. (II) After gas-vitrectomy 0.8ml FMCH were injected in 4 rabbit eyes. 4-6 days later the eyes were enucleated and examined histologically.

(I) All investigated PFCL could be removed completely with FMCH. Retained portions of FMCH itself were detectable in small amounts. After fluid-air exchange these portions became smaller depending on time.
(II) In all animals an increasing irritation of the anterior segments and development of intravitreal gas were observed. Histologic examination revealed drop-down of photoreceptors nuclei and vacuoles in the retinal pigmentepithelium even apart of this the regular retinal structure was maintained.

Conclusions: FMCH is suitable as a solvent agent for the investigated PFCL. However FMCH itself can not be completely removed with simple aspiration. Therefore the use of FMCH as a wash-out solution is only practical if it is removed as completely as possible, its intra-ocular remnants vaporize and leave the eye as gas or can pass the tissue to be removed with the bloodstream better then other PFCL. This is especially important since our results demonstrate in rabbits that large intravitreal remnants of FMCH may lead to major ocular side effects. Probably these are due to the high vapor pressure of FMCH.

1 Dept. of Ophthalmology, University Kiel, Hegewischstr. 2, D-24105 Kiel
2 Clinic for Ophthalmology, University Regensburg;
3 Pharm Pur GmbH, Augsburg;
4 University-Eye-Hospital Lübeck;
5 Pharamceutical Institute, University Kiel.

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