Study of the efficacy of intravenous tissue plasminogen activator (tPA) in the treatment of acute central retinal artery occlusion (CRAO)

INTERVENTION: Intravenous infusion of tissue plasimonogen activator (tPA) versus standard therapy Tissue plasminogen activator will be given at dosage of 0.9mg/kg in 100ml of normal saline over 1 hour. Standard therapy group will be given placebo therapy of Normal saline 100ml over 1 hour. The therapy will be randomised in a 1:1 ratio using a block randomization schedule. The infusion will be covered in black cover for masking. CONDITION: Central Retinal Artery Occlusion ‐ Acute stroke of the eye Retinalvascular disease PRIMARY OUTCOME: Greater than or equal to 3 lines of visual acuity on Snellen visual acuity chart or equivalent conversion SECONDARY OUTCOME: 1. Visual fields using Humphry Visual Field Analyser with SITA‐Standard 24‐2 strategy in those with visual acuity greater or equal to 6/60. ; 2. Nerve fiber layer thinning using Optical coherence topography at 6 months compared to baseline. Visual acuity change of 3 lines or more according time to presentation between 0‐6 hours, 6‐12 hours and 12‐24 hours. Visual acuity change on Snellen Chart or equivalent converstion INCLUSION CRITERIA: INCLUSION CRITERIA: 1. Age greater than or equal to 18 years old 2. Acute central retinal artery occluasion (CRAO) within 24 hours of onset of symptoms (ie within 24hours of last know time with normal vision) 3. A presumed thromboembolic cause 4. No evidence of temporal arteritis by clinical assessment or laboratory studies (e.g., erythrocyte sedimentation rate [ESR]) 5. Non‐contrast computerized tomography (CT) brain demonstrating no acute intra‐cranial haemorrhage, infarction or mass lesion 6. Computerized tomography angiography (CTA) demonstrating no ipsilateral carotid artery occlusion.