Perfluorocarbon liquids (PFCLs) have been used widely in vitreoretinal surgery. They are a decent tool which flatten the retina in retinal detachment (RD) surgery, peel fibrous membranes in proliferative vitreoretinopathy, protect the fovea when manipulating dropped lenses, or dissect membranes in diabetic patients [1,2]. PFCLs are low viscosity fluid which are odorless and colorless in nature, and much heavier than water [2]. These characteristics make PFCLs to pull out subretinal fluid and flatten the retina from posterior to anterior.

The use of PFCLs during surgery is known to be safe even with their large volume; however, if remained longer in the eye, their toxicity has been reported in animals and humans when retained more than 48 hours [3,4]. The toxicity might cause inflammation in the eye, and PFCLs should be removed before the surgery ends.

Here, we would like to report a case that showed toxicity of PFCLs when remained intraocular for a long period of time. To best of our knowledge, this is the first report to demonstrate intraocular toxicity of PFCLs other than inf lammation, and its clinical presentations were different from other reports. Written informed consent for publication of the research details and clinical images was obtained from the patient.

A 72-year-old man was referred to our clinic for rhegmatogenous RD in his left eye. He had bullous inferior RD from 3 to 9 o’ clock, and macula was involved. The retinal break was at 9 ‘o clock for about 1 disc-diameter, and 3 o’ clock for about half disc-diameter. Initially, pars plana vitrectomy with intravitreal C₃F₈ (16%) gas tamponade was performed. When gas was 70% left, inferior RD was observed. Hence, we performed encircling with 240 silicone band, and 276 tire with silicone oil tamponade (5,700 cs, 6 mL). Before switching to silicone oil, PFCLs (perf luorooctane [C₈F₁₈], 0.69 centistoke at 25 °C; Perfluorn, Alcon) were used to flatten the inferior retina.

After the surgery, the retina was flat, but intraocular PF- CLs still remained in intravitreal space (Fig. 1A-1C). Unfortunately, the patient was lost to follow-up for 6 months, leading to the inadvertent retention of residual PFCLs and silicone oil in the eye for an extended duration of approximately 6 months. We removed silicone oil and remnant PFCLs immediately after patient visited our clinic, but the patient exhibited a distressing clinical picture characterized by marked chorioretinal atrophy predominantly in the inferior retinal regions (Fig. 1D). The loss of inner and outer retinal tissue, contraction of the choroid, and the presence of the bare sclera were found (Fig. 1E-1I). Despite the severity of retinal degeneration, the patient’s visual acuity remained relatively stable at 10 / 25, a circumstance attributed to the sparing of the central foveal region from the degenerative process. Consequently, this observation reinforced the contention that the atrophy primarily targeted gravity-dependent areas of the retina, while sparing regions crucial for high-acuity vision.

In this case, intraocular PFCL unintentionally remained for 6 months and resulted in tremendous chorioretinal atrophy which was considered to be related to the posture during sleep. PFCLs possess a higher specific gravity compared to intraocular fluids, rendering them prone to gravity-induced migration. This characteristic made inferior retinal regions vulnerable to increased mechanical stress. The mechanical forces exerted by PFCLs on the dependent areas of the retina could explain the atrophic changes observed in this case.

While PFCLs have traditionally been regarded as valuable adjuncts in vitreoretinal surgery due to their physical properties, this case demonstrates that their extended presence can provoke complex retinal pathology that diverges from the anticipated outcomes. Furthermore, PFCLs have been demonstrated to induce toxicity in human retinal pigment epithelial cells over a span of approximately 7 days [5]. It not only sheds light on the potential for intricate PF- CL-induced retinal toxicity but also highlights the need for meticulous patient follow-up and thorough removal of even minimal remnant PFCLs after surgery. Thus, surgeons need to be vigilant about the various aspects of complications related to PFCLs, which include both their intrinsic toxicity and the gravitational mechanics that play a role in causing subsequent harm.