Letter of response to “Safety of perfluorocarbon liquids cannot be the retinologist responsibility” by Carlos Pastor

Abstract

Dear Editor, We thank Pastor for his letter regarding our paper “Benchmarking different brands of perfluorocarbon liquids” as he is an experienced specialist in the field of intraocular tamponades. He criticizes that our work lacks a clinical orientation, although the paper was in the retinal disorders section. It was not the aim of this paper to investigate any relationship to clinical factors, and the allocation to a particular section was done by the editor, not by the author. Pastor’s criticism that PFO (perfluorooctane) toxicity in cases of intraocular permanence for long periods of time hasn’t seemed to arouse much interest in the companies selling them cannot stand like this. Responsible manufacturers emphasize in the relevant IFU that perfluorocarbon liquids (PFCL) are only suitable for intraoperative use andmust therefore be completely removed from the eye at the end of surgery. Therefore, “intraocular permanence for long periods of time” is an example of off-label use, and the adverse events occurring during “intraocular permanence for long periods of time” cannot serve as evidence that the manufacturers and their consultants somehow don’t care about such adverse events. The interest in acute toxicity, also in at least parts of the industry, is amply proven by publications [1, 2]. We do not understand why it needs to be clarified that we only mentioned the countries that have reported problems, failing to mention the countries where these products were manufactured. What is the point of mentioning “the countries where these products were manufactured” for the supposed “lack of clinical orientation”, when the manufacturers were clearly named—a fact that enables interested parties to determine the country of origin? Pastor points out the possibility that the prevalence of PFOinduced toxicity may be even greater than currently known because many ophthalmologists do not report suspected cases to Health Agencies for fear of legal consequences. In context with this sufficiently well-known dilemma, it is important to require that complaints and reports contain sufficient data on the identity of the products used. Without such data, a systematic root-cause analysis becomes meaningless. He further states that it is difficult to understand how countries where toxic PFO were manufactured like Germany, Turkey, and India have not publicly reported a significant number of toxicity cases within their own countries. As far as Germany is concerned, it could well be that simply, no toxic events have occurred in Germany, as German vitreoretinal (VR) surgeons are extremely cautious about using new PFCL or silicone oil products that are not well known. The problems and discussions within the German VR Society and German Ophthalmological Society with and on stickiness and solubility of partially fluorinated admixture in PFCL have brought about a definite awareness thereof and result in cautiousness here. If such problems had occurred, they would have been discussed within the VR community. Problems with tamponades have always been reported on as soon as they occurred, especially by Kirchhof’s group in Cologne and Hoerauf’s group in Goettingen (e.g. [3, 4]). Since tamponade developments were mainly initiated in Germany, the German VR surgeons tended to and continue to be acutely aware of potential problems and adverse events. The fact that, in Pastor’s opinion, it is incomprehensible that there are no reports of toxicity cases originating from Germany, it is very likely because none in fact occurred, or if any did, they were not attributed to PFCL. The aim of this work was not to establish a clinical correlation between the H-value and biological effect/toxicity, but to show that incidents with CE-certified PFCLs do not show that PFCLs are dangerous per se, but rather the fact that various manufacturers are either unaware of the possible risks or unable to produce highly pure products that are then safe when * Joachim H. Dresp