[Ocular tissue after intravitreous silicone oil injection. Histologic and electron microscopy studies]

The intraocular tolerance of silicone oil is still a matter of ongoing controversy. To evaluate a possible migration of silicone oil into eye tissues we examined various tissues from eyes that were injected with silicone oil for a period of 6 months to 3.5 years. The histological and ultrastructural characteristics of these tissues are reported (cornea, 4 cases; iris, 3 cases; retina, 8 cases; retinal pigment epithelium and optic nerve, 1 case). In the iris and in corneas showing a perforating injury light microscopy revealed vacuoles presumably lying in the cytoplasm of macrophages. Using immunohistochemistry and electron microscopy, macrophages could also be found in the retina of eyes that had been filled with silicone oil for longer than 6 months. Using energy dispersive X-ray analysis, vacuoles could be identified as storage sites of the silicone oil. This observation demonstrates that a long-term silicone oil tamponade may cause a migration of silicone oil into the retina and other ocular tissues. In order to prevent this complication, removal of silicone oil should be performed as early as possible.