Eye sight weak after brain surgery?

sir my sister is a brain patient. she is 30 years old. in 2007 we did a brain surgery operation to the doctor... now the situation is her eye site is have been very weak. we checked her to the doctor eye speaciallist. he said sorry her eye site have been so much down and i can not recommend a glasses,because glasses would not work ( but i recommend the eye drop its name called "systane" . so now we are using systane. her eyes site is so much weak she can not see anything clearly.