Ophthalmology Diseases of orbit, Lids and lacrimal apparatus 1fe5bc9c Most common cause of unilateral proptosis is- A Thyrotoxicosis B Retinoblastoma C Intraocular haemorrhage D Raised intracranial tension High-Yield Explanation *Thyroid orbitopathy is the most common cause of bilateral and unilateral proptosis. Ref: Head & Neck surgery 2nd/e p.1513