[Histopathological and ultrastructural characteristics of oil-associated complications in silicone oil-filled human eyes].

OBJECTIVE: To observe morphological changes of oil-associated complications in silicone oil-filled human eyes, and to further explore their pathogenesis.

METHODS: The morphology analysis and immunohistochemistrical study were performed in 25 specimens including 8 eyeballs, 1 ocular content, 4 preretinal membranes, 4 corneal buttons and 8 lens from human eyes with silicone oil tamponade. Two of preretinal membranes acquired freshly were also evaluated by transmission electron microscopy (TEM).

RESULTS: Endothelium cell loss (90%) and band keratopathy (83%) were the most typical changes in silicone oil-associated keratopathy;while epithelial cell fibrosis was the most frequent histopathological features in silicone oil-associated cataract. In 8 eyeballs and 1 ocular content, it was found that damages to normal retinal layers and formation of preretinal or subretinal membrane with extensive silicone bubbles were obvious in the cases of silicone oil-associated retinopathy, which included loss and degeneration of neuron cells. Moreover, in 3 eyeballs with silicone oil for more than 60 months, retinas were completely replaced by fibril membranes, and the oil vacuoles were also found in sclerocorneal scar, trabecula, iris, ciliary body, choroid, optic nerve and its tunica vaginalis. These finding demonstrated that the longer the silicone oil was retained in eyeballs, the more severe its complications were. Different sizes of silicone bubbles in 2 preretinal membranes were noted easier by TEM than light microscopy. There were some macrophages marker (CD68) positive staining cells in the tissues filled with silicone bubbles, such as preretinal or subretinal membrane and optic nerve. Partial of the membranes surrounding the oil bubbles was positive for GFAP staining, and other part was positive stained for Vimentin.

CONCLUSIONS: Intraocular silicone oil can damage the normal tissue structures and function if it is retained in eyeballs too long. This results suggest that silicone oil should be removed timely after the retinal reattachment stabilized and can not be used as a kind of long term intraocular tamponade.