In a case of anisocoria, when 1% pilocarpine le is instilled into the eye with abnormally dilated pupil, no response occurs. Cause of anisocoria may be:

Ans is 'c' i.e. Pharmacological blockage Anisocoria (inequality of pupillary size) implies disease of the efferent (motor) nerve of the light reflex, iris or muscles of the pupil.If, on application of pilocarpine 1% in each eye, the affected pupil reacts little or not at all and the unaffected pupil constricts normally, the pupil is not dilated because of innervation problems but because of a problem in the sphincter muscle, itself. Non-neuronal causes of mydriasis are:Anticholinergic mydriasis (e.g., scopolamine (hyoscine), cyclopentolate, atropine).Traumatic iridoplegia (sphincter rupture, pigment dispersion, angle recession).Angle-closure glaucoma (ischemia of the iris sphincter).Fixed pupil after anterior segment surgery.Bound down iris (synechia) after iritis."