Hi welcome to HCM ,
Since you haven't mentioned about the age of the person concerned, in general ocular involement in Arnold Chiari syndrome
includes double vision/ jerky eye movements(nystagmus
) and sensitivity to light. There are studies which say ,late onset nystagmus post decompression surgery reverts back to near normal within a period of approximately 3 mths.And MRI
is best diagnostic tool for Arnold syndrome
Since you have mentioned as Blind individual, I would suggest to go for a MRI and a neurosurgeons opinion on the post surgical status as the recovery of vision depends on the cause of visual loss.
Hope this helps .Take care.