Abstract: A portable screen assembly for use in combination with a series of visual acuity testing cards to test the visual acuity of an infant or otherwise functionally young (handicapped) person requiring to be held by another person comprises a three-panel screen wherein two side panels are hingedly connected to a main panel in such manner that they can be moved from folded positions overlying the back face of the main panel to positions wherein each defines a predetermined obtuse angle with the front side of the panel. A removable and collapsible brace connects the upper free corners of the side panels to hold the screen assembly in its erected position, and this brace cooperates with the main panel and a bracket of rod material to support a shield which blocks the line of view between the person holding the person under test and an opening in the main panel where successive acuity testing cards are presented to the person under test.