Hi Yvonne, my son is 550+ long sighted on his right and left is plano (near perfect) and is being treated for lazy eye currently. Dr Pauline Cheong will be able to provide you with good explanations, i seeked 2nd opinion from her. But they will need specs definitely.
Based on my understanding, all babies are born long sighted and as they grow, the long-sighted will be corrected. Reason for the kids being so far-sighted is due to not so good eye development. As they grow up doing all the "near activities" such as reading, using computer. They start to develop myopia hence the far-sighted act as a "buffer" and will be reduced to a certain extent coupled with growing up development of the eye. My 2 cents worth.