Usefulness and limit of silicone in management of complicated retinal detachment

Among various substances used for intraocular tamponade in the treatment of vitreous opacity and complicated retinal detachment, silicone oil is superior to hyaluronic acid or sulfur hexafluoride. Its low gravity and hydrophobic nature permit good tamponade effect to be obtained and its high transparency allows us to detect remnant vitreous traction in the far periphery and/or retinal tears. Furthermore, preretinal membrane can be peeled off easily after silicone oil removal. The hydrophobic nature of silicone prevents clouding due to postoperative hemorrhage and fibrin reaction. It should also be stressed that intravitreal silicone oil suppresses iridial rubeosis or prevents its development. However, the use of silicone has limitations, since it gives rise to various complications that include pupillary block glaucoma, secondary glaucoma, cataract formation and corneal complications including band-shaped keratopathy. Pupillary block in aphakic eyes can be prevented by placing peripheral iridectomy at the 6 o'clock position, since silicone is lighter than water. After silicone injection, glaucoma is more often seen in diabetic aphakic eyes than in phakic or nondiabetic eyes. On the other hand, corneal complications were less frequent in diabetic than in nondiabetic eyes; in nondiabetic eyes the complications were more frequent in aphakic than in phakic eyes. Due to possible complications, silicone should be removed after a certain follow-up period, during which time detection and management of the causes of redetachment of the retina are possible due to the high transparency of silicone.