<prompt> All are true about central retinal artery occlusion CRAO except?Most commonly occurs due to thromboembolismAnterior chamber paracentesis is used for treatmentSudden painful loss of visionOccurs due to obstruction of retinal artery at the level of lamina cribrosa  <response>: Ans. a Most commonly occurs due to thromboembolism; c Sudden painful loss of visionRef: Kanski 7e, p. 559, 563 Presentation is with sudden and profound loss of vision, Painless, except in Giant cell arteritis Atherosclerosis related thrombosis at the level of lamina cribrosa is by far the most common underlying cause of CRAO, accounting for 80 cases 