<prompt> Finchams test differentiates cataract fromConjunctivitisIridocyclitisOpen angle GlaucomaAc. Congestive Glaucoma  <response>: The coloured halos in primary angle closure glaucoma must be differentiated from those found in acute purulent conjunctivitis and early cataractous changes :-In conjunctivitis, the halos can be eliminated by irrigating the discharge.The halos of glaucoma and immature cataract may be differentiated by Finchams test in which a stenopaeic slit is passed across the pupil. During this test glaucomatous halo remains intact, while a halo due to cataract is broken up into segments. 