Hi The children with cone dystrophy are likely to have subnormal vision. At all cost she should wear her refractive correction, her diet should be such that she has good intake of vitamin A rich and antioxidants in food. Antioxidants have shown to help such patients, but in such small children they should be given under medical supervision. Gene therapy is another treatment on which research is going on. These children are likely to have low vision, so they should be trained according to their special needs. School staff should be appraised about their problem and family members should always keep this in millpond. Coming four years till the age of seven years are crucial for visual development in brain , see to that she should be seeing in best possible mannera and doing all sort of work that is visually demanding eg even the computer games etc. an article on disease cone dystrophy by Kellogg s university is detailed and good. You may read it. Take care