Edwin Seet1, Chandra M Kumar1, Tom Eke2, Girish P Joshi3. 1. From the Department of Anaesthesia, Khoo Teck Puat Hospital, Yishun Central 90, Singapore. 2. Department of Ophthalmology, Norfolk and Norwich University Hospitals, Norwich, United Kingdom. 3. Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, Texas.