MCA Code of Safe Working Practice for Merchant SeaFarers


The bright light from the sun reflecting off the surface of a calm sea or from ice caps in the Polar regions, or from the vessel itself, can dazzle the seafarer and cause damage to the eyes.


In these conditions, seafarers working on the bridge or on the open deck should wear sunglasses, which are an important piece of protective equipment, rather than tinted eye protection. For protection on the bridge, collective protection systems should always be considered; for example, sunblinds.


The following guidance should be considered when purchasing sunglasses.

  • The lens tint should be neutral – ideally either grey or brown as these cause the least colour distortion.
  • The lens tint should be no darker than 80% absorption.
  • A graduated tint, with the darkest at the top of the lens, lightening towards the bottom, may be useful.
  • Glasses should be CE marked and to the British Standard BS EN ISO 12312-1:2013+A1:2015. BS EN ISO 12311:2013 ensures that the sunglasses offer a safe level of ultraviolet protection.


Photochromic lenses react with UV radiation by darkening. Sunglasses with photochromic lenses must not be worn during the hours of darkness as they can significantly reduce night vision. Information is given in MGN 397(M+F).



Polarised lenses reduce the amount of light passing through the lens by selective filtering of certain electromagnetic spectral planes. The use of this type of lens should also be discouraged. However, in some situations; for example, when navigating in shallow water, the wearing of these lenses may be beneficial as they can reduce the reflected glare from the surrounding water. Polarised lenses must not be used when viewing instrument panels as the visibility of some images may be unclear.



All frames should be well fitting and large enough to allow sufficient protection from oblique sunlight. All seafarers requiring a spectacle prescription must have a clear pair of correcting lenses but can have prescription sunglasses as their second pair. The wearing of non-prescription sunglasses on top of prescription glasses is not permitted. For navigational watches during the hours of darkness, the wearing of any type of sunglasses is not recommended.


Download full MCA Code here.