The "Sighted Blind"

The 'sighted blind' is a good description of some children who quite apparently are sighted because they can move freely, do not bump into objects, grasp objects based on visual information and yet they do not use their vision to explore structures and they do not respond in usual testing of visual acuity or contrast sensitivity. However, they may be able to tell where Hiding Heidi is hiding, or where the gratings are located. In these children visual information appears not to be available for any type of form analysis, but they are able to make effective use of motion information and have awareness of the space around them despite having little or no visual capability to look at pictures.

In some children the loss of form analysis may be only on one side of the visual field. This is most commonly seen in the hemiplegic children on the side of hemiplegia. In Goldmann perimetry and in automatic perimetry there may appear to be a total loss of that half field, but a confrontation visual field may be measurable, especially if the child is asked to point where s/he sees something moving in the peripheral field, not to tell when the movement appears. In this group of children measurement of flicker sensitivity across the visual field is a new assessment technique to assess function in the "blind" hemifield.

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