<prompt> A woman complains of coloured haloes around lights in the evening, with nausea and vomiting, IOP is normal; Diagnosis isIncipient stage glaucoma open angleProdromal stage, closed angle glaucomaMigraineCluster Headache  <response>: B i.e. Prodromal stage of closed angle glaucoma In Prodromal Latent stage of angle closure glaucoma there occurs an attack of transient rise in IOP 40-60 mmHg lasting for few seconds only Q. Such attacks are intermittent and are usually precipitated by overwork, anxiety, fatigue or due to dilation of pupil as reading in dim illumination, or watching cinema in a darkened cinema hall Q. During this phase patient experiences transient blurring of vision, coloured halos around the light due to corneal oedema and mild headache Q. On examination eye is white and not congested. Anterior chamber is narrow and gonioscopy reveals narrow angle. 