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Editor,—Perfluorocarbon liquids (PFCLs) used in combination with silicone oil have been suggested as a method of achieving superior and inferior retinal tamponade in phakic eyes.1 2 Because of toxic effects of PFCLs in animal studies, they are not recommended for long term tamponade.3 We report on a case in which, owing to unforeseen circumstances, both silicone and perfluorodecalin were left in an eye for 6 months.
A 71-year-old man presented with a right subtotal retinal detachment and a left partial detachment. Preoperative visual acuity was hand movements in the right eye and 6/9 in the left. The right retina had marked proliferative vitreoretinopathy and multiple holes in the inferior and superotemporal regions. Retinal reattachment was achieved using an air-fluid exchange but it was impossible to obtain adequate support of the inferior breaks by the use of an explant or silicone oil alone; therefore, a mixture of 1000 cSt silicone oil and perfluorodecalin was used to act as a temporary tamponade with a view to early removal, and an explant was placed in the superotemporal quadrant. It was possible to treat the left retina with an explant alone.
Because of a cardiac arrest postoperatively, further surgical intervention was delayed by 6 months. By this time, although the retina remained attached, a dense cataract had developed and an inverse hypopyon had formed. Right phacoemulsification with intraocular lens implant and removal of silicone oil and heavy liquid was carried out. A third fluid component, more dense than either silicone oil or perfluorodecalin, was noted intraoperatively.
One week later, the right retina redetached via a superonasal entry site tear. This required reinsertion of silicone oil with encirclement. At 6 months’ follow up both retinae were flat with a visual acuity of counting fingers in the right eye and 6/5 in the left. Intraocular pressures have remained normal and the right cornea has remained clear.
Perfluorocarbon liquids used in combination with silicone have been suggested as a method of achieving retinal tamponade in retinal detachments with inferior and superior pathology.1 2Because of differing densities, PFCLs can support the inferior retina and silicone oil the superior aspect. As both substances are immiscible, a meniscus is seen between them on fundal examination (Fig1). With the exception of perfluorophenanthrene (Vitreon), PFCLs have been shown in animal studies to be toxic to the retina and corneal endothelium when left in situ for any period of time. Other complications of chronic hypotony or chronic raised intraocular pressure seen clinically may be related to preoperative or intraoperative factors rather than the use of PFCLs.3Perfluorodecalin has been effective in the treatment of giant retinal tears when removed 5 days postoperatively4 and the use of perfluorophenanthrene as a short term vitreoretinal tamponade was limited to 4 weeks in an initial study.5 There have been no reports of perfluorodecalin used in combination with silicone being left in an eye for 6 months.
Although our patient did develop a cataract and emulsified silicone in the anterior chamber, intraocular pressures have been normal and the cornea has remained clear. The third mixture found intraoperatively probably represented emulsified perfluorodecalin within silicone oil. We were unable to reproduce this mixture in vitro by combining perfluorodecalin and silicone, suggesting the presence of an emulsifying agent in vivo. The strongest emulsifiers of silicone demonstrated by in vitro experiments are fibrinogen, fibrin, and serum.6 Finally, a visual outcome of counting fingers with preservation of the visual field suggests worthwhile retinal function and that, long term, intraocular perfluorodecalin may be tolerated by the retina.