A Turville–Stewart Diagnostic Unit by Raphael’s Ltd, London with set of fusion/suppression slides.” A mid‑20th‑century ophthalmic instrument used to test binocular vision, suppression and retinal correspondence, dating to about 1950/60. The cream‑painted handpiece with rotating disc and interchangeable metal slides (marked 01, CS, R1, R2, RF1, RF2) is an ophthalmic fusion / suppression tester, part of the Turville–Stewart binocular diagnostic system.​ Different slides carry small apertures and coloured filters; with the viewing tube attached and the unit aligned to a chart, the examiner presents separate images to each eye and varies filters and apertures to assess fusion, retinal correspondence and suppression in patients with squint or binocular vision problems.​ Raphael’s Ltd, London, supplied optometric and ophthalmic equipment through the mid‑20th century, and references to the Turville–Stewart Diagnostic Unit appear in optometry literature from the 1950s onwards.​ This item is untested and offered as a collectible/display item.