Use a comma:
A family friend of mine had begun to lose her
vision, and she...
When you are trying to write well, avoid statements of the obvious. It's important, because in real life people do not often state the obvious! So, it is unnatural. Do not write, "Eyes are one of the most important senses that anyone can possess."
You should maybe condense this whole thing into three good sentences, and then go on to get deeper in your discussion of opthamology. What do you know about new advances in technology, new surgical procedures, etc.? Show them that you are passionate about this field -- impress them with your educational and career goals. Maybe you are hoping to find a cure for retinitis pigmentosa, or maybe you hope to join some famous researcher at this university.
Kevin, EssayForum.com