Chang S, Zimmerman NJ, Iwamoto T, et al.. Experimental vitreous replacement with perfluorotributylamine
ABSTRACT Perfluorotributylamine, a liquid fluorochemical used in artificial blood substitution, was evaluated for potential application as a vitreous substitute having heavier density than saline. It was injected into the vitreous of 38 rabbit eyes after mechanical vitrectomy or gas compression of the vitreous with perfluoropropane. The eyes were observed for periods of up to five months. Clinically the liquid occupied the lower vitreous space but gradually dispersed into smaller fluorochemical droplets. In the upper vitreous clusters of cells appeared within three to four weeks which precipitated on the posterior lens surface and in the cortical vitreous. In eyes with experimental retinal detachment perfluorotributylamine had physical properties which provided mechanical retinal tamponade. Its interfacial tension prevented passage through iatrogenic retinal breaks. Histopathologic findings showed irregularly shaped defects in the outer segment disks as early as two days after vitreous replacement. These changes appeared to reverse if perfluorotributylamine was removed after two days. The cellular response in the vitreous consisted primarily of monocyte-derived macrophages capable of ingesting fluorochemical (foam cells).
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- "These are fully fluorinated alkane compounds with a high specific gravity. However, these compounds turned out to be unsuitable long-term internal tamponade because of the mechanical damage on the retina and the tendency for droplet dispersion   . Presently, these compounds are widely used as intraoperative tools, but not as vitreous sub- stitutes. "
ABSTRACT: In the past two decades, many advances have been made in vitrectomy instrumentation, surgical techniques, and the use of different tamponade agents. These agents serve close retinal breaks, confine eventual retinal redetachment, and prevent proliferative vitreoretinopathy (PVR). Long-acting gases and silicone oil are effective internal tamponade agents; however, because their specific gravity is lower than that of the vitreous fluid, they may provide adequate support for the superior retina but lack efficacy for the inferior retina, especially when the fill is subtotal. Thus, a specific role may exist for an internal tamponade agent with a higher specific gravity, such as heavy silicone oils (HSOs), Densiron 68, Oxane HD, HWS 45-300, HWS 46-3000, and HeavySil. Some clinical evidence seems to presume that heavy tamponades are more prone to intraocular inflammation than standard silicone if they remain in the eye for several months. In this review, we discuss the fundamental clinical and biochemical/molecular mechanisms involved in the inflammatory response after the use of heavy tamponade: toxicity due to impurities or instability of the agent, direct toxicity and immunogenicity, oil emulsification, and mechanical injury due to gravity. The physical and chemical properties of various HSOs and their efficacy and safety profiles are also described.BioMed Research International 07/2014; 2014:574825. DOI:10.1155/2014/574825 · 2.71 Impact Factor
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- "Studies in rabbit, guinea-pig, mouse, owl monkey, cat and tiger salamander show that if the potassium siphoning into the vitreous does not work, the subretinal space might be used as an alternative sink (Newman 1987; Newman & Reichenbach 1996). Long-lasting potassium accumulation causes subsequent retinal degeneration; in our study, however, only inner retinal degeneration was encountered, possibly because the outer retinal layers are still protected by means of alternative siphoning mentioned above (Chang et al. 1987; Stolba et al. 1997). "
ABSTRACT: To characterize the concordance/symmetry of each retinal layers in individuals without macular pathology and to further characterize the localization of inner retinal thinning in eyes receiving silicone oil-based endotamponade. Retinal layers of one hundred eyes of 50 individuals without macular pathology were imaged using spectral domain optical coherence tomography (SD-OCT) and manually segmented using ImageJ software (developed by Wayne Rasband, NIH, Bethesda, MD, USA). In the second part of the study, retrospective analysis of 3028 cases of pars plana vitrectomy in University Eye Hospital Cologne, Germany, was conducted, retrieving nine patients with silicone oil-based endotamponade with no macular condition interfering retinal layers measurements. These patients had retinal detachment not involving the macula due to various conditions. In these patients, retinal layer segmentation was performed and compared with the fellow eye. There is a moderate-to-high concordance for all retinal layers between the right and the left eye of the same individual. In eyes receiving silicone oil-based endotamponade, the inner retinal layers become subsequently thinner. Ganglion cell and inner plexiform layers contribute most to this thinning, that is, 0.537 ± 0.096 mm(3) compared with 0.742 ± 0.117 mm(3) ; p = 0.006. Outer retinal layers were not affected by silicone oil-based endotamponade (p = 0.439 for the differences of calculated outer retinal layers). Ganglion cell and inner retinal layers become subsequently thinner after the use of silicone oil-based endotamponade. This study advocates the use of spectral domain optical coherence tomography for patient management with silicone oil endotamponade to early detect subsequent retinal thinning.Acta ophthalmologica 11/2013; 92(4). DOI:10.1111/aos.12307 · 2.51 Impact Factor
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ABSTRACT: The vitreous body of a fresh human eye removed post-mortem was suspended in water after stripping off the corneo-scleral coat, the choroid and the retina. Coloured ink was injected into the vitreous specimen from different points. Individual spaces (cisterns), transitions between cisterns and specialized structures like the bursa premacularis and the canal of Cloquet became visible when partial filling had taken place. SEM-examination of the individual cisternal walls of the bursa premacularis area showed networks of different density and texture and a considerable variation in the length of the individual fibres, some of which extended from the ciliary body (Retzius bundles) to the rim of the Bursa premacularis.Documenta Ophthalmologica 01/1987; 67(1-2):183-96. DOI:10.1007/BF00142712 · 1.11 Impact Factor