Your letter came just as I was celebrating my 94th birthday -- and now someone has to read my mail to me, because I too suffer from what's called age-related macular degeneration, or growing blindness.
Has it been easy to adjust to this? Not really; I miss not being able to pick up a newspaper and read it or read my Bible the way I once could. But instead of focusing on what I can't do as the disabilities of old age increase, I try instead to focus on what I still can do. I still have some vision; I still can move about to some degree; I still can spend time with my children and grandchildren (and now great-grandchildren).
Most of all, I still can enjoy God's presence every day. I can pray; I can encourage others; I can meditate on the promises God has given us in His Word, the Bible; I can thank God for His faithfulness to me over the years. God's promise is true: "Even to your old age and gray hairs I am he, I am he who will sustain you" (Isaiah 46:4).
Don't give in to despair. Instead, give your life to Jesus Christ, and ask Him to help you adjust to whatever comes your way. Above all, thank Him that someday all the pains and sorrows and disabilities of this life will be over and we will be safely in God's presence forever.