I think I need glasses and my visit to the optometrist has confirmed this. I've never worn glasses, and I'm new to all this, so I don't completely understand how things work.

These past few weeks, I find that on some days my eyesight is nearly perfect. Everything is sharp, no matter the size (such as text). However, on other days, my eyesight is really bad. Things are really blurry, and although I can read text on my computer or far away, it is a bit more difficult to do so. Although not super blurry, the difference is quite significant.

Has anyone had these experiences before? Is this normal?


1 Answer 1


There are a lot of factors involved. I'm no authoritative expert, but here are my personal observations about visual acuity fluctuations and optical knowledge, since getting LASEK (PRK) 6 years ago.

  1. inflammation - My right eye is more likely to get inflammed, which will cause loss of acuity. Sleeping in an awkward position could cause this. DO NOT RUB YOUR EYES no matter how much they itch - it will reshape your cornea.

  2. Eye strain - if you work on a computer > 8 hours a day like me, your focus can get stuck at a certain distance, but this is only temporary. Letting your ciliary muscle relax by staying 3 feet away helps a lot. Blinking and taking breaks also help.

  3. Loss of contrast sensitivity instead of focus - I once was accidently blinded by a laser projector like they use in night clubs. It's like looking at the sun, but worse. It took a few hours to recover completely. I think the same can happen if your monitor is too bright. Also good to reduce the blue light level.

  4. Are you confusing night vision with daylight vision? - In the dark with your pupil wide open, acuity will be poorer due to a larger part of the cornea being used, which exposes more imperfections, and causes more distortion.

  5. Tired or haven't excercised? - Your brain has to do a lot of signal processing to see, so if you're fatigued, then it will be dulled. Same as with hearing.

see comment

  • Thanks for the suggestions and information. For #1, rubbing your eyes really can damages them?
    – samseva
    Dec 19, 2016 at 2:07
  • I'm convinced rubbing your eyes will reshape the lens (cornea) because I found a while ago if I temporarily made the lens more round (concave) by slightly pushing inward on the eyelid (see picture), the slight blur in my right eye goes away. The improvement is most noticeable when looking at a bright spot against a dark background like a traffic light. Since I did have a habbit of rubbing my right eye, I conclude that probably flattened the cornea a bit. But you don't have to take my word. Lots of other sources say not to rub.
    – Yale Zhang
    Dec 29, 2016 at 5:47
  • Okay. Thanks for heads up.
    – samseva
    Dec 30, 2016 at 20:41

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