Spectroscopic evidence of microstructural alterations in retrieved 1,000-cSt PDMS Silicone oil tamponades

To evaluate the in vivo physicochemical stability of retrieved intraocular silicone oil by means of 1 H-NMR and FT-IR spectroscopy and to explore the association of detected spectral alterations with clinical and surgical factors. Twelve silicone oil retrieved from patients who underwent planned removal of 1,000-cSt intraocular tamponade after pars plana vitrectomy for rhegmatogenous retinal detachment were analyzed. A lot-matched unused silicone oil sample served as the control. Microstructural alterations were assessed by 1 H-NMR and FT-IR spectroscopy, and spectroscopic findings were compared with retrospectively collected clinical and surgical parameters. Associations between binary spectral outcomes and clinical variables were evaluated using Fisher’s exact test (p = 0.05). Spectral alterations suggestive of microstructural changes were identified in a subset of retrieved silicone oils by both 1 H-NMR and FT-IR analyses. FT-IR alterations were significantly associated with extensive laser photocoagulation (p = 0.010) and partial retinal detachment extent (p = 0.010). No significant associations were found between spectral alterations and tamponade duration, clinically observed emulsification, revision surgery, proliferative vitreoretinopathy, or epiretinal membrane formation. In selected cases, concordant spectral alterations across 1 H-NMR and FT-IR supported the consistency of the detected samples. Retrieved 1,000-cSt silicone oil may not remain completely physicochemically inert after intraocular use. The observed spectroscopic alterations appear to be more closely related to surgical and retinal disease–related stress factors, particularly extensive laser photocoagulation, than to tamponade duration or clinically evident emulsification. These findings support the hypothesis that the intraocular microenvironment may contribute to molecular-level destabilization of silicone oil and highlight the need for further mechanistic and longitudinal investigations. These exploratory findings should be regarded as hypothesis-generating and require confirmation in larger, prospective studies.