I work with blind people every day. Not all of them became blind because of bad lifestyle choices. Some were born blind but for those who became blind as an adult, for the most part, there ware multiple factors for some including genetics that you speak of that are a factor. It could be that you were just living such a healthy lifestyle that it delayed the onset of Fuch's? Bravo for you if that is the case. My questions about lifestyle choices were just that...questions. I was throwing out a lot of possibilities and none of them stuck. I had very little to go on from what your friend said to determine what might have been the cause. I hope you were not offended by my broad statements about the causes of Fuch's. I am glad you wrote.
This is my opinion but there may have been some kind of mineral deficiency or toxic chemical that could have triggered your genetic pre-disposition toward blindness or Fuch's disease much like vaccinations often trigger Autism. Did you take any kind of anti-biotics or receive vaccinations before the onset of Fuch's?
Most people have an Iodine deficiency. You might start there and try some of the suggestions I made to see if there is any that help. Best wishes for you and your stuggle to heal your body.