Which property of heavy silicone oil makes it suitable as a long-term tamponade agent in recurrent inferior proliferative vitreoretinopathy?

• A Specific gravity greater than water, allowing it to sink and tamponade the inferior retina ✓
• B Lower viscosity than standard silicone oil, permitting easier injection through small gauge systems
• C Higher surface tension than all intraocular gases
• D Rapid absorption into surrounding ocular tissues over 2 weeks

Explanation

Heavy silicone oils such as Densiron 68 have a specific gravity above 1, so they settle dependently and provide tamponade of the inferior and posterior retina, exactly where standard silicone oil (specific gravity below 1) floats away from. Standard 1000 centistoke oil is preferred for superior pathology. Heavy oils are still removed later because prolonged retention causes emulsification, inflammation and keratopathy, so option D is physiologically wrong.

Reference: Ryan's Retina, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.