The Look-See method involves a single (Visual) modality.
 
 
It is their theory that the children will learn to understand the written words in a natural manner similar, to how they learn the spoken language.
Children who are deaf can be taught to read through this approach.
Problems can become significant, however, if a child has a visual processing (perceptual) problem.  
For example, some children have a poor awareness of position in space and/or spatial relation.  In these instances, serious confusions in the reading process can occur.
The child may not, for example, be able to differentiate between the letters ãnä, "c" and "u"; or "d", "p", "q" and "b"; or "m" and "w", etc. etc.  Or, between words like "was" or  "saw".  
 NOTES:  Explore some more information on the Whole Language Approach. 
 NOTES:  Still more information on the Whole Language Approach.