Hi, I Am A 57 Years Old Woman. From My

Hi, I am a 57 years old woman. From my childhood, about at age 14, I have strange feeling with my eyes.
Sometimes I feel that focus in my eyes going narrow and to read one word I have to bring it very close . I can not see by my side vision,everything in dark. ( It is like same when you have been under the sun for long time)
This can last about an hour and be gone itself. This happens at least once a month. What is this?
I have -2,5 on my both eyes.