Perfluorocarbon Liquid for Dissection of Proliferative Vitreoretinopathy: Avoiding Subretinal Persistence

Dear Editor, I read with interest the article titled " Subretinal Perfluorocarbon Liquid for Dissection of Proliferative Vitreoretinopathy " by Dalma-Weiszhausz et al. 1 Perfluorocarbon liquids (PFCLs) effectively stabilize the retina and facilitate efficient repair of complex retinal detachments due to proliferative vitreoretinopathy (PVR). PFCLs however, have some drawbacks 2 which may be avoided by applying certain maneuvers. Residual subretinal PFCL may appear when aspirating PFCL through a peripheral retinectomy under balanced salt solution (BSS) which occurred in 20% of cases in the described series. 1 Residual postoperative subretinal PFCL can be toxic, migrating subfoveally and producing scotomas. 3 If limited to extrafoveal regions, small PFCL remnants may be left behind. 4 Direct aspiration (using a 39-or 49-gauge cannula) via an extrafoveal retinotomy, inferior displacement of the subretinal bubble with BSS, fluid-air exchange and upright positioning are different techniques employed to remove subfoveal PFCL. In order to reduce the risk of retained subretinal PFCL, the eye can be tilted during aspiration to displace PFCL to the periphery (close to the ora serrata). There is a 2.3% risk of residual subretinal PFCL when using 20-gauge vitrectomy instruments. However, applying 23-gauge instruments is associated with a 4.5-fold increased risk of this condition. 8 Subretinal PFCL remnants occurred in 16.7% of patients undergoing 23-or 25-gauge microincision vitrectomy surgery (MIVS) for management of giant retinal tears. 9 Dalma-Weiszhausz and colleagues did not specify the gauge of the applied vitrectomy instruments, aspiration cannula, and aspiration flow rate in their report. 1 Smaller-gauge vitrectomy instruments are more likely to result in retained subretinal PFCL due to their higher flow rate, therefore, disruption of surface tension will create small residual subretinal PFCL bubbles. 8 This can be avoided by exerting pressure from a simultaneous preretinal PFCL bubble, which can simplify retinal reattachment besides providing a smooth convex subretinal surface during PVR removal (Fig. 1). The surgical technique Dalma-Weiszhausz and colleagues employed may predispose subretinal PFCL entrapment within funnel-shaped retinal detachments, as the liquid can approach the funnel and get stuck away from the retinectomy. This complication may be prevented by the use of simultaneous preretinal PFCL in situ. This technique can hinder the formation of residual subretinal PFCL bubbles at the time of aspiration since the preretinal PFCL displaces the bubbles beneath the retina. This method ensures complete PFCL evacuation and that the liquid does not dissociate into smaller bubbles which may get entrapped near the equator …