Classification of Vision Impairment

The World Health Organisation’s Classification of Visual Performance, though no longer widely used, offers educators a frame of reference regarding the ability of children with vision impairments to function visually.

Normal Vision

  • Snellen acuities: 4/6, 6/6 [Log MAR: -0.2, 0.1] OR Fields: 180°, 140°
  • No impairment

Near-Normal Vision

  • Snellen acuities: 6/9, 6/18 [Log MAR: 0.2, 0.5] OR Fields: 120°, 80°
  • Slight vision impairment, though should be able to perform all visual tasks
  • Likely to be eligible to drive a car

Moderate Low Vision

  • Snellen acuities: 6/24, 6/48 [Log MAR: 0.6, 0.9] OR Fields: 60°, 30°
  • Moderate vision impairment which will require the use or aids and/or accommodations/adaptions for some tasks in the learning environment

Severe Low Vision

  • Snellen acuities: 6/60, 6/120, 3/60 [Log MAR: 1.0, 1.3] OR Fields: 20°, 15°
  • Severe vision impairment which will require the use of aids and accommodations/adaptions in the learning environment
  • May be eligible for additional funding due to vision impairment

Moderate Blindness

  • Snellen acuities: 6/150, 6/300, 3/75 [Log MAR: 1.4, 1.7] OR Fields: 10°
  • Will require the significant use of aids and accommodations/adaptions for most tasks in the learning environment
  • Likely to be eligible for additional funding due to vision impairment

Severe to Total Blindness

  • Acuities: HM (hand movements), LP (light perception), NLP (no light perception) [Log MAR: -] OR Fields: 0°
  • Will require the significant use of aids, other senses and the provision accommodations/adaptions for all tasks in the learning environment
  • Likely to be eligible for additional funding due to vision impairment

Adapted from: Colenbrander, A. A Dimension of Visual Performance. Trans. Am. Acad. Ophthalmol. Otolaryngol. 1977 83:332 – 337.

For more information visit: Vision and Vision Impairment.