Science can restore a sense of sight to th blind, even those who have never seen, Professor L. Kay, of Canterbury University's electrical engineering department, told the science students' conference in Christ-church.

All The Benefits of sight could be obtained through hearing, he said.

Professor Kay cited the bat, blind yet able to intercept its manoeuvrable prey, the moth, by using acute hearing, which picks up high frequency sound waves bounced off objects. The bat's brain has been developed to interpret the echoes in the same way as man interprets visual images.

Thus the bat "visualises" the object without analysing the sound. The insects, with their different shapes, give off a different sound pattern to the bat's ears.

The professor said that, although the bat is naturally able to receive and emit high-frequency sound waves, this does not prevent man from using his technology to improvise a similar system—and Professor Kay has been doing research on this.