Eyes go really blurry randomly?

What does it mean when your eyes get blurry but then go right back to normal within seconds? Any ideas?

• For the past three weeks every time I'm reading, writing or focusing on something for more than a few seconds [basically anything that needs a little concentration], my eyes get blurry - but then if I blink a few times or just wait a few seconds my eyes go back to normal. It's like when you look through a camera that has to be manually adjusted and the picture is out of focus. The longest it's ever lasted is six seconds. Normally it's less than three though. There have been no changes in my diet, no weight loss or gain, no difference in my health since this started. I was in a bad car accident in May - but all surgeries, physical therapies and rehab have already been completed. I am still on pain medications, but only take them rarely. I've had a cat scan and an MRI [since my doctor tends to over test for everything =D Not saying it's a bad thing - just saying]. Nothing has show up. I'm wondering if anyone has experienced this and what it ended up being? Or any suggestions on what it could be - if anything? Please don't tell me to see a doctor. I know that Y!A is in no way a substitute for a doctor or actual diagnosis, I'm just trying to get an idea as to what this is or why it's happening. Also, as I mentioned, I have seen a doctor. Thanks. =D

• Answer:

  I received a traumatic brain injury in the military when a high speed chase turned bad and my MP vehicle was struck head-on. The blurred vision problem happened to me frequently for a couple of years afterward. Now, since having been diagnosed with insulin dependent diabetes, I find that even slightly higher than normal blood sugar levels has the same effect. If you were in a serious vehicle accident this past year I would suggest that as possibly the reason. I'm assuming, of course, that your physician has already tested your blood glucose and ruled out diabetes. Best wishes!