What is the eye sight criteria for a Certificate of Vision Impairment (CVI)?

An ophthalmologist (optician) will use a combination of both your visual acuity (a measurement of how well you can see detail) and your field of vision (the portion of space in which objects are visible at the same moment during a steady fixed gaze in one direction) to judge whether you are eligible to be certified, and at which level.

To be certified the best acuity and visual fields achievable with both eyes open is considered against the criteria, therefore if you can see well with one of your eyes then the criteria would not be met. Please see Can I get a CVI and register as sight impaired (partially sighted) if I have lost the sight in one of my eyes?

If you have a good visual acuity, you will usually have had to have lost a large part of your visual field in both eyes to be eligible to be certified.

Alternatively, if you have all your visual field, you will usually have to have a very poor visual acuity in both eyes to be eligible to be certified.

Generally, to be certified as severely sight impaired (blind), your sight has to fall into one of the following categories, while wearing any glasses or contact lenses that you may need:

  • Visual acuity of less than 3/60 with a full visual field
  • Visual acuity between 3/60 and 6/60 with a severe reduction of field of vision, such as tunnel vision
  • Visual acuity of 6/60 or above but with a very reduced field of vision, especially if a lot of sight is missing in the lower part of the field

To be certified as sight impaired (partially sighted) your sight has to fall into one of the following categories, while wearing any glasses or contact lenses that you may need:

  • Visual acuity of 3/60 to 6/60 with a full field of vision
  • Visual acuity of between 6/60 and 6/24 with a moderate reduction of field of vision, cloudiness in parts of your eye, or your lens has been removed and not replaced with a lens implant
  • Visual acuity of 6/18 or even better if a large part of your field of vision, for example a whole half of your vision, is missing or a lot of your peripheral vision is missing

People who do not automatically meet the criteria may still be considered for registration under exceptional circumstances at the discretion of the consultant.

Fluctuation in vision

Some people have vision that fluctuates, meaning they would meet the criteria on some days and circumstances, but not on others. These circumstances can relate to things like light level or changes in general health. A common example is someone who has keratoconus (a condition that can be helped with lenses), they would not usually be considered eligible. They may not reach the certification criteria when wearing their contact lenses, even though they are unable to tolerate their lenses for the full length of a working day and would meet the criteria without them.

For information on visual acuity, please see What is visual acuity?,

For further information on registration and CVI's please see our Registering sight loss section.

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