We examined the light intensity delivered by the Trachlight™ reusable lightwand and the effect of repeated sterilisation on this light intensity. Using a light meter and test chamber, the light intensity of 12 new Trachlights and 31 Trachlights available in operating theatres was measured. In addition, five new devices underwent 30 repeated sterilisations with light intensity measurement after each cleaning. There was no difference between the light intensity of new Trachlights (median (IQR [range]) 2282 (2202–2780 [1970–4400])) lux and the devices currently in service (2295 (2018–2796 [1649–3280]) lux (p = 0.27)). The median (range) number of uses for devices currently in service was only 3 (0–9). There was, however, significant light intensity loss after 10, 20 and 30 cleanings (p = 0.001). After 10 cleanings, the mean light intensity was 75% of initial output, and after 30 cycles, light intensity was 59% of initial output.