Any precautions before surgery

Although surgery is planned after obtaining a fitness,
patient should inform doctor about previous allergies, surgeries. Patients with
history of heart attack should obtain fitness from cardiologist as should a
diabetic from his diabetologist Similarly patient should inform the surgeon
about any unusual discharge, redness on the day of surgery.

I have been advised to have silicone oil or gas at the end of surgery . Which is better?

Outcome of surgery is not dependent on either gas or silicone oil as both can achieve same results. Which is best should be left to discretion of the operating surgeon. Only difference is that gas  needs no second surgery as it gets slowly absorbed. To remove silicone oil a second surgery is needed. Its important to AVOID AIR TRAVEL for minimal of 6-8 weeks when gas is used.