"I see," said the blind man to his deaf daughter*

* I often heard this saying as a child - my dad was the one who usually said it.

Since my LASIK surgery, my vision gets better and better everyday.
I had a check-up last week, and I have a pet peeve. The receptionist sits me in the special chair with all the eye equipment attached. On the wall, across the room, is the eye chart. I usually have to wait 5 minutes before the doctor comes in. I usually fill my time looking at all the things around the room, including the eye chart.
Then the doctor comes in, and he has me read the eye chart with each eye. He usually has me read the same 2 lines with each eye. Then he moves the special eye equipment into place and proceeds to check both eyes, and I will again read the same two lines on the eye chart.
What is my pet peeve?
I have seen the same lines on the eye chart so many times that I know what the letters are. How does that check my vision when I know it goes ---- A ---- P----O, etc? I even know that there is always a number at the end of each line. It starts with 6 then the next line ends with 5 and the next line ends with 4 and you *think* the next line will end with 3, but here is the trick - it actually ends with a 5!
Shouldn't they be changing up the letters if they really want to check my vision? And shouldn't they have the eye chart covered when I am waiting for the doctor? This would prevent people from looking at it with both eyes (I could stand right in front of it and memorize it if I wanted to - but I don't).