Sorry for the long post, but I wanted to include all information that might be relevant. I have a lot of questions, so I listed them all at the end.
I had lasik on both eyes 3 months ago and I am experiencing a lot of eye strain and headaches. After lasik, my left eye is a little weaker than my right eye. I think this is one factor causing the eye strain and I am wearing glasses to try to balance my eyes. The glasses help reduce the symptoms, but I still have eye strain and headaches every day.
I get the most eye strain when doing things that involve sustained visual focus (computer, reading, driving), but I can get eye strain doing just about anything. After awhile, my eye muscles start to hurt and I just want to unfocus or close my eyes. It becomes difficult to concentrate. Pain will sometimes develop behind one eye or between my eyes and a headache will often follow. Closing one eye usually feels better. Sometimes I wear an eye patch while reading. I also experience a different type of strain sometimes when moving my head or eyes or changing focus from one place to another. I'll get a brief pulse of pain in my eye, but it is not a sustained feeling of strain like I get when staring at a computer screen. Trips to the store can cause a lot of strain. I think all this strain is cumulative and by late afternoon, I'll usually have sore eye muscles and a headache. I experience these symptoms even on days when I avoid using the computer or reading, but it is not quite as bad. Basically the only way to completely avoid the eye strain is to keep my eyes closed all day.
Some background: I am 33 yrs old. I wore soft contacts for 15 yrs, but discontinued about 2 yrs ago due to discomfort. The Rx I was wearing for the last several years was -3.75 OU (contacts) and -3.75 -.25 OU (glasses). I spend most of my work day in front of a computer, and I did not have eye strain problems before lasik. I usually took my contacts out after work and wore glasses in the evening.
Here are the numbers from my pre-lasik refraction:
Manifest: -3.75 -.50 OD, -4.00 -.25 OS
Cycloplegic: -3.25 -.50 OD, -4.00 -.25 OS
The cycloplegic right eye value is odd to me since my eyes seemed like they were very similar to each other before lasik.
Possible eye strain factors:
Refractive Imbalance - My current refraction is plano or -.25 OD, -.50 OS. No cylinder. The glasses I am wearing are plano OD, -.50 OS. I've tried a few other pairs as well, but these seem to provide the most comfort. Distance vision in my right eye is very good without glasses. I don't really want more correction in that eye since it would just add strain for near vision. If I wear glasses that are plano OD, -.25 OS, my right eye is still stronger. If I wear glasses that are plano OD, -.50 OS, my left eye is a little stronger. So the imbalance between right and left is somewhere between .25 and .50 diopters. Since glasses only come in .25 diopter increments, I still have up to .12 diopter imbalance with glasses. That doesn't sound like much, so it seems like there must be other factors causing eye strain.
Exophoria / Convergence Insufficiency - The ophthalmologist confirmed I have a small amount of exophoria. I don't get double vision so I must be able to compensate easily. I have read that this is common and likely not a problem. The minus lenses in my old glasses were reducing the amount I needed to converge, so perhaps eye muscles are straining due to the extra convergence demand now. This seems unlikely since I wore contacts for so long without strain. Also, before lasik I used to read sometimes without glasses and had to hold the book fairly close due to my nearsightedness, and I didn't get strain. I was told to try pencil push-ups which I've been doing for a few weeks. I can converge up to the tip of my nose, although it hurts within a few inches. I can't focus within about 6 inches anyway so I don't have much need to converge closer than that. I haven't noticed any reduction in strain at reading or computer distances, unfortunately.
Dry Eyes - I have dry eyes, which causes a lot of discomfort at times, but it feels much different than the eye strain described above. The discomfort from the dryness is more of a burning sensation and feeling of air blowing on my eyes. It is usually more of a problem in the late evening, but can occur during the day. Perhaps it is somehow contributing to the eye strain and headaches, but I'm not sure how. I've tried using lots of artificial tears for a day and it didn't seem to have any effect on eye strain. I have lower punctal plugs in both eyes that were inserted about 2 months ago and are supposed to dissolve after 3 months. I use preservative free artificial tears sometimes in the evening and Genteal Gel at night.
Light Sensitivity - I seem to be more sensitive to light after lasik. Maybe this is a factor. I feel better with low ambient light. I see a lot of glare when the sun reflects off cars and things. I also have moderate night halos and starbursts. The glare, halos, and starbursts are annoying, but are much lower concern for me than the eye strain, headaches, and dry eye.
Questions...lots of questions:
1. Is it unusual that I am not able to tolerate a refractive imbalance of around .37 diopters without eye strain?
2. Do you think I would eventually adapt without glasses if given enough time (months/years)? I waited 7 weeks after lasik before wearing glasses and did not adapt in that time. It would be nice if I could adapt to this since the weaker eye might help with reading as I get older.
3. Is it possible that my vision system is so sensitive that a refractive imbalance of .12 diopters with glasses on is causing eye strain?
4. Is it possible to buy glasses in .12 diopter increments anywhere? I'd like to try some with -.37 in left eye just to see if it helps.
5. Should I consider a lasik enhancement to my left eye to target .37 diopters more correction to try to match my right eye?
6. What kind of accuracy could I expect if -.37 is targeted for enhancement?
7. Is the accuracy of laser correction generally a percentage of targeted correction? Or is there some additional fixed tolerance just due to lifting and replacing the flap?
8. Would an enhancement increase the risk of developing permanent dry eye? Or would it just set me back to where I was 3 months ago.
9. Do you think exophoria or convergence insufficiency could be causing my symptoms now, even though I didn't have the symptoms with contacts?
10. If so, should I try wearing glasses with base IN prism? I am reluctant to do this since I could become dependent on them.
11. Do pencil push-ups work for adults?
12. Do you think dry eyes could be contributing to the eye strain and headaches I described? How?
13. What else could be causing my eye strain symptoms? Any advice?
Thanks for reading.