Hi, I Was Already Wearing Glasses Since I Was 12

Hi, I was already wearing glasses since I was 12 (I am 27 now). It was around 200 both eyes initialy and I was able to maintain it to around 275. To my surprise, I checked it again this year and it was already 300. Again, when I went to have my glasses changed October this year it was already 400. What could possibly caused the sudden increase? Thank you doc