A women less than three months pregnant [does that matter] has 10 children [does that matter] and is expecting number 11, is going blind in one eye. Expert advice by top doctor says the pregnancy is causing the blindness. Can she abort to save her eye. P.S. This was a real issue, and despite the doctor's advice the abortion was not performed and she indeed lost sight in her eye. The doctor who was consulted would like comments for future reference.
The Rambam says you can only abort if the baby is trying to kill its mother. This makes abortion in regards to your question, still an act of evil as the mother’s life was not threatened. The second answer says that if the baby’s is trying to harm the mother or in anyway harms her health, then it must be aborted. This suggest that the quality of life (sight) is important. I am not a doctor neither a rabbi. You should really ask your rabbi this.