The phenomenon of "sticky" silicone oil

To investigate the reasons for difficulties removing silicone oil from the vitreous cavity due to putative adherence to the retina. Gas chromatography-coupled mass spectroscopy of the headspace (GC/MS/HS) and gel permeation chromatography (GPC) were used to detect volatile compounds in silicone oil samples explanted from patients, qualitatively as well as quantitatively. Surface and interfacial tensions of the explanted samples were measured using the pendent-drop technique. To simulate the removal of silicone oil from the vitreous cavity, the contact between silicone oil and differently treated surfaces and various aspiration techniques were tested in vitro. The median concentration of perfluorodecalin in seven "sticky" samples was 2.4 times higher than in 14 non-sticky samples. In the sticky samples, the median surface tension of the aqueous phase was lower. The difficulty of aspirating silicone oil could be reproduced in vitro by reducing the surface tension of the aqueous environment of the silicone oil. The observed stickiness of silicone oil seems to be a matter of reduced surface tension of the surrounding aqueous material and/or contamination of silicone oil with perfluorocarbon liquid, which creates interruption of the material flow, giving the impression of adherence of the silicone oil to the retina.