Moyamoya Disease, Double Bypass Surgery, Stroke, Optical Nerve OK, Taking Medicine

My son 10yrs, was diiagnosed with moya moya in Dec 2008 after he suffered a stroke in the left side of brain due to constriction of left carotid artery . This affected his speexch also. He is recovering well. He was on valporate after a double bypass surgery in March 2009 in Japan to help both sides of the brain get better blood supply. In 2011 Dec unfortunately, a shaow infract was detected in Dec 2011 after three years of the surgery. This was in the optical and perietal region of the right side of brain. His vision was affected and cortical blidness and left anopia has resulted. His vision is improving but we have been told that it will not be the same as in the past. It is now 6/18. His fundus and optical nerve is ok. He has started ecospirin 75 and cloba. A padeatric neurologist has suggested a chaneg. The new medicines are lametec 25, colyspirin 100 (instead of ecospritin), Cloba to contuinue and Homochek (multivitamin). Should we switch to new medicine?