Abstract
Purpose :
Silicone oil (SO)-related vision loss (SORVL), a new concept of unexplained SO-related complication, has recently emerged. The purpose of this study is to evaluate our hypothesis of SORVL (1) high concentration of inflammatory cytokines in sub-SO fluid (SOF), (2) electrolyte abnormality in SOF, (3) light-induced damage under surgical microscopic in SO-filled eye.
Methods :
For the hypothesis (1) and (2), we compared major inflammatory cytokine and electrolyte levels between SOF and anterior chamber fluid (ACF). We also evaluated the correlation of inflammatory cytokine levels and the changes of central retinal thickness (CRT). In addition, we examined cultured human Müller cell viability after adding SOF in the culture medium. For the hypothesis (3), we injected different amount of SO and photosensitive paper in the laboratory model eye. We captured the images of photosensitized papers in SO-filled model eye and examined the difference of light exposure density depending on the amount of SO.
Results :
We analyzed inflammatory cytokine levels from in total 55 SOF, 22 ACF, and 10 vitreous fluid (VF) from eyes with rhegmatogenous retinal detachment (RRD), proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), macular hole-associated retinal detachment (MHRD), and macular hole (MH). IL-10, IL-12p40, IL-6, MCP-1, and VEGF in the SOF with PVR were significantly higher than in those with RRD or MHRD. The levels of IL-8 and MCP-1 in SOF were significantly higher than those in ACF. CRT changes during SO endotamponade were not correlated with the presence of any inflammatory cytokines. Levels of ferrous iron, but not of potassium, showed a significant difference between SOF and VF. Cell viability assay showed that SOF-added medium induced higher Müller cell viability than VF-added medium. Light exposure density with 1.0% coaxial light was approximately 22-fold higher than that with 0.1% light. Furthermore, it was approximately 34-fold higher in eyes with +20 diopter IOL than in those with no IOL. The density in eyes with 75% SO was the highest among all groups (0%, 50%, 62.5%, 75%, 87.5% and 100% SO).
Conclusions :
Corroborating these results indicated that highly concentrated inflammatory cytokines and electrolyte abnormality in SOF are less likely, but light-induced damage under coaxial illumination from the surgical microscope into ~75% SO-filled eyes is possibly the cause of SORVL.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.