Safety and effectiveness of intravitreal injections in the silicone oil-filled eye

Silicone oil (SiO) use has gained acceptance in providing an effective long-term tamponade in retinal detachments complicated with proliferative vitreorretinopathy. As the use of injectable therapeutics grows and their indications broaden, it is important to know the safety and effectiveness of intravitreal injections in eyes containing SiO as a vitreous substitute. Thus, whereas intrasilicone injection of bevacizumab is safe and effective to treat patients with iris neovascularization after vitrectomy for advanced proliferative diabetic retinopathy, triamcinolone injection into the SiO-filled eye is inadequate given that it might significantly increase the IOP due to volume expansion. Furthermore, triamcinolone may not dissolve in SiO, preventing its diffusion to the macula surface, and its whitish crystals might opacify the visual axis. Unlike intravitreal triamcinolone, the DEX implant causes minimal volume expansion and no media opacity. It is biodegradable and injected without surgery and thus also advantageous over the fluocinolone implant. Additional studies are necessary to better understand the pharmacodynamics of sustained-release drugs from devices implanted or inserted into eyes filled with SiO as vitreous substitute.