Biocompatibility of intraocular liquid tamponade agents: an update

Abstract

Intraocular liquids tamponade agents, such as perfluorocarbon liquids (PFCLs), semifluorinated alkanes (SFAs), silicone oils (SOs) and heavy silicone oils (HSOs), are a crucial intraoperative and/or postoperative tool in vitreoretinal surgery, in particular for the management of complex vitreoretinal diseases. However, their use is not without complications, which are potentially severe. Consequently, a growing interest has been devoted to the biocompatibility of these compounds and the adequacy of current regulations that should guarantee their safety. Obviously, an updated knowledge on research findings and potential risks associated to the use of intraocular liquid compounds is essential, not only for vitreoretinal surgeons, but also for any ophthalmologist involved in the management of patients receiving intraocular liquid tamponades. In light of this, the review provides a comprehensive characterisation of intraocular liquid tamponades, in terms of physical and chemical properties, current clinical use and possible complications. Moreover, this review focuses on the safety profile of these compounds, summarising the existing regulation and the available evidence on their biocompatibility.

Retinal and Corneal Changes Associated with Intraocular Silicone Oil Tamponade

“…Silicone oils with nominal η of 1000, 1300, 2000, 5000 and 5700 mPa∙s are currently available for use in vitreoretinal surgery. Except for η, the physicochemical properties of these chemicals do not vary significantly based on the different MW ( Table 1 ), thus η is the main parameter influencing the choice of a certain SO in the surgical practice [ 2 , 39 ]. In particular, higher η has been associated with increased resistance of SO to emulsifying in vitro, but also with more difficult surgical handling [ 40 ].…”

“…As mentioned above, SO are currently used for the management of complex vitreoretinal diseases [ 2 ]. Compared to gaseous tamponades, SO offer several advantages, including longer or permanent tamponade, compartmentalization of the eye with a reduction in the diffusion of pro-angiogenic molecules into the anterior segment, and better visualization of the retina, as well as better visual acuity for the patient in the early postoperative period and decreased risk of slippage of retinectomies, postoperative bleeding and chronic postoperative hypotony [ 47 ].…”

“…The most common indication for SO tamponade is represented by complex retinal detachments (RD), mainly associated with proliferative vitreoretinopathy (PVR) or at high risk of postoperative PVR (i.e., posterior and/or multiple or giant retinal tears, concomitant choroidal detachment and/or ocular trauma and/or uveitis) [ 2 , 48 , 49 , 50 ]. With regard to the presence of preoperative PVR, SO may be associated with reduced risk of postoperative chronic hypotony when compared with C3F8 [ 5 , 51 ].…”

“…Thus, on the one hand, the clinically detectable SO droplets may represent only a minimal part of the whole SO emulsion; on the other hand, an uncertain amount of small SO droplets may be present intraocularly in absence of any clinical evidence. Emulsified SO droplets may play a crucial role in the pathogenesis of most of the complications potentially associated with SO tamponade, such as intraocular inflammation, ocular hypertension, glaucoma, keratopathy, optic neuropathy, epiretinal membranes (ERM), and fibrosis [ 2 , 56 , 61 , 74 , 75 ].…”

“…Silicone oils (SO) are liquid intraocular tamponades, classified as class IIb medical devices within the European Union, i.e., implantable, surgical invasive devices for long-term use (>30 days) [ 1 ]. Silicone oils have been traditionally used and have still an irreplaceable role in the surgical management of complex vitreoretinal diseases [ 2 ]. However, their use can be associated with potentially severe complications, whose pathogenetic mechanisms remain not fully understood [ 3 ].…”