Ophthalmic surgeon Hugh Wright Thomson worked with Trotter to develop the skiascope which he used initially for eye examinations in school children although he subsequently also found it helpful for adults in hospital refraction work. A long stem was attached to its centre and the circular frame was fitted with twenty of the lenses most commonly used in retinoscopy (technique to objectively determine the refractive error of the eye – farsighted, nearsighted, astigmatism – and the need for glasses).]]> John Trotter Ltd.; 1867-2014; Optician and instrument maker]]>