[Experimental study on usefulness of silicone-fluorsilicone copolymer oil (SiFO) in vitreoretinal surgery].

Purpose: To evaluate the usefulness of silicone-fluorsilicone copolymer oil (SiFO) as an intraoperative tool and a vitreous substitute in vitreoretinal surgery.
Methods: Handling properties of SiFO were tested and compared with those of perfluorooctane (PFO). The transparency of both substances was measured by spectrophotometry and subjectively assessed. Their tendency to dispersion was observed during injection in balanced saline solution (BSS) and after mechanized and manual shaking. Ease of injection and aspiration through small-gauge instruments was evaluated. Ocular tolerance to SiFO and PFO was studied after intravitreal injection in rabbit eyes: intraocular pressure, anterior segment inflammatory response and dispersion were evaluated, and a histopathological study was performed.
Results: Injection and aspiration of SiFO were more difficult than those of PFO because of its higher viscosity. PFO dispersed progressively into small droplets as early as two days after intravitreal injection, whereas SiFO remained as a single bubble for 14 days. Histopathologically both substances induced an inflammatory response over the inferior retina, with microvacuolated macrophages and foreign body giant cells, which were larger in eyes wearing SiFO.
Conclusions: SiFO may be useful as an intraoperative tool, although its main drawback is a more difficult injection and aspiration compared to PFO. It has been well tolerated as a short-term vitreous substitute, but further clinical studies are needed.