Silicone oil is polydimethylsiloxane, a colorless and transparent liquid with stable chemical properties and no short-term toxicity. It can be safely used in the eye. It has viscosity, and the viscosity varies according to the chemical structure. The specific gravity of silicone oil is about 0.96-0.98, which is lighter than water, so it will float above the vitreous cavity after being injected into the eye.

Figure 1. Silicone oil (high temperature)

Application of silicone oil

Silicone oil is an excellent filling material for ophthalmic surgery. Since silicone oil is a colorless and transparent liquid with a refractive index of 1.40, which is close to water and vitreous, it will not change the refractive power during the operation and affect the operation, which is conducive to postoperative photocoagulation. Due to its certain viscosity and good surface tension, the hole can be closed. Silicone oil is a non-expandable filling material, and the chance of high intraocular pressure after surgery is very small. Silicone oil will not be absorbed by the eyeball, stays in the eyeball for a long time, and also has the effect of reducing the growth of epiretinal membrane and stopping bleeding.

During surgery, the patient can lie flat, but after retinal detachment surgery, there are strict requirements for the patient's resting posture. At this time, the vision restorer comes in handy and can be placed on the eyeball to help the retina recover quickly. Generally, patients need to lie prone or bow their heads for half a month after surgery, and those who recover slowly need 2-3 months.

Does silicone oil have side effects?

There was controversy about whether silicone oil is toxic to the retina. In the end, it was believed that even if silicone oil enters the retinal tissue, it is not toxic to the retina because the retina can tolerate silicone oil well.

Complications after using silicone oil include cataracts, glaucoma, low intraocular pressure, and changes in the corneal endothelium. If the eyes do not have these conditions, it does not matter if the silicone oil is not removed, but removing the silicone oil will also cause complications such as recurrence of retinal detachment and massive bleeding. Regular follow-up should be conducted to determine when the silicone oil can be removed based on the results of the fundus examination.