Painless sudden loss of the vision occurs in all EXCEPT

(Acute angle closure glaucoma) (229- Khurana 4th)Acute primary angle closure glaucomaSymptomsSigns* Pain*- sudden onset severe pain in the eye radiates to the branches of 5th nerve* Rapidly progressive impairment of vision** i.e., painful* Nausea vomiting, prostrationsConjunctiva - Chemosed , congestedCornea - Oedematous, congested* Anterior chamber- shallow** Angle of AC is completely closed* Iris - discoloured* Pupil - semidilated, vertically oval and fixed* Optic disc is oedematous and hyperaemicCauses of painless loss of vision - obstruction of CRA, CRV, cranial arteritis , Ischemic papillitis, Migraine, Retro bulbar neuritis vitreous haemorrhage, Retinal detachment, Macular holes, cyst or haemorrhage, Hysterical blindness