Long-term assessment of eyes in which silicone oil injection had been used in the treatment of retinal detachment with massive preretinal retraction was undertaken in 92 consecutive patients. While a high incidence of complications, particularly cataract, was confirmed, this study showed that they were probably caused not by any toxic effect of silicone oil but by obstruction of normal metabolic exchange at the silicone-tissue interface. The incidence of complications causing deterioration of vision or serious symptoms was not found to be high, and navigating vision was well preserved.