Children without form vision

The World Health Organisation (WHO) definition of paediatric low vision for educational purposes, written in Bangkok in 1992, extends the concept of low vision to all children with even minimal visual function (Management of Low Vision in Children - Report of a WHO Consultation, Bangkok, 23-24 July 1992. WHO/PUBL/93.27, World Health Organisation, Programme for the Prevention of Blindness, Geneva, Switzerland.).

Children in Groups I and II need functional assessment although their vision cannot be measured with the usual visual acuity tests. If a child has no light perception, it is still important to know whether (s)he had vision earlier, especially, whether there was useful vision during the early motor learning and during the development of spatial concepts. Discussion with the child about light, vision, shadows etc is easy if the child has had vision in early childhood and can remember some visual images. The educator and the child have to make a special effort to develop these concepts if the child has never had visual function.

Light Perception and Light Perception with Projection may sound similar but mean different visual functions especially in orientation and mobility. Light perception means awareness of presence of light without being able to tell where the light source is located. To "project" means the ability to identify the direction of the light source. It is important to assess whether the child can perceive the direction of light equally well in all parts of the visual field or whether the projection is more reliable in the right or left half field or a quadrant of the visual field. Even vague awareness of the direction of the light source is helpful for spatial orientation.

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