The safety-critical aspect of NDT essentially demand good visual acuity - particularly wrt hair-line cracks using dye-penetrant methods. Nevertheless, this can be achieved wearing normal spectacles, and I would expect ND testers to have the odd magnifying glass in their toolkit. In that respect though, that would be nothing out of the ordinary, and not a "health and safety" issue in the normal accepted sense. UNLESS of course you have a DSE issue arising from fairly constant scrutiny of component x-ray scans/plates or ultrasound displays; perhaps on a production line with a fairly fixed workstation layout? So- what's your NDT method and process? p.s. it's non-destructive, not "none".

DSE covers micorfiche and film-readers. I take it your people are looking at some sort of back-illuminated viewer as opposed to peering at a 35mm strip! ;-)

Are they required to wear safety specs? If so then they may need presciption ones. A well known high street chain sells safety specs vouchers that include an eye check so this may resolve your issue