A glare visor for reducing received ambient light intensity presented to a wearer viewing a helmet-mounted display and an external display, the ambient light being of visible optical wavelengths, the glare visor comprising a glare visor body of optically transparent material being partially absorbing of light of visible optical wavelengths thereby to reduce the intensity of ambient light transmitted therethrough to the wearer, the glare visor body having a wearer-facing surface and an outward-facing surface, wherein the glare visor is positioned, in use, to: receive, at the outward-facing surface, external display light intended to pass through the glare visor for viewing by a wearer, the external display light including a given wavelength(s) of light; and receive, at the wearer-facing surface, HMD display light which, if reflected by the glare visor, is visible to the wearer, characterised by the visor body having a transparent optical coating formed upon the outward-facing surface of the visor body, the coating being partially transmissive to said light of visible optical wavelengths and preferentially transmissive to light of a sub-range of said visible optical wavelengths that includes the given wavelength(s), such that any HMD display light that is received at the wearer-facing surface is required to pass through the partially absorbing material of the visor body before reaching the transparent optical coating and, if reflected at the coating, will be directed to pass back through the partially absorbing material of the visor body towards the wearer, the glare visor thereby obtaining an increase in contrast between external display light that includes the given wavelength(s) and is received at the outward-facing surface, relative to the ambient light, and suppressing ghost images formed by reflection at the coating of HMD display light that is received at the wearer-facing surface. receive, at the outward-facing surface, external display light intended to pass through the glare visor for viewing by a wearer, the external display light including a given wavelength(s) of light; and receive, at the wearer-facing surface, HMD display light which, if reflected by the glare visor, is visible to the wearer, characterised by the visor body having a transparent optical coating formed upon the outward-facing surface of the visor body, the coating being partially transmissive to said light of visible optical wavelengths and preferentially transmissive to light of a sub-range of said visible optical wavelengths that includes the given wavelength(s), such that any HMD display light that is received at the wearer-facing surface is required to pass through the partially absorbing material of the visor body before reaching the transparent optical coating and, if reflected at the coating, will be directed to pass back through the partially absorbing material of the visor body towards the wearer, the glare visor thereby obtaining an increase in contrast between external display light that includes the given wavelength(s) and is received at the outward-facing surface, relative to the ambient light, and suppressing ghost images formed by reflection at the coating of HMD display light that is received at the wearer-facing surface.