Visual acuity

Hi -- I just read your response to another post about the VEP test, and I'm wondering if that test would be helpful in my case. I find that no matter what glasses prescription I try, I don't see clearly even though I'm told I see 20/20 when reading the chart at the eye doctor's office. For lack of a better term, things look kind of shadowy or not sharp (though not blurry or double). I'm 44, and I've been attributing the problem to the fact that I have frequent migraine headaches and chronic light sensitivity, as well as a strong eyeglass prescription (-750 in the right eye, with cyl +075 and axis 180; -675 in the left eye; and +175 bifocal in both eyes); plus I go back and forth between contacts and glasses.

I did have a brain MRI in August 2005 due to the migraine symptoms; also, periodically my left pupil is slightly more dilated than the right one. The brain MRI showed a few non-specific, focal lesions in the white matter; my neurologist thinks both these lesions and the dilated left pupil are migraine related. In September 2004, I also had a cervical spine MRI because of some tingling in my hands and feet; the MRI was normal, but further testing showed mild small-fiber neuropathy (which appears to have been post-viral).  

For a time, I was very worried about MS, but I've been assured that my neurological symptoms have other causes. My question for you is whether chronic migraine activity and/or a strong prescription could cause shadowy vision, or would further testing (such as the VEP) possibly be needed. Thank you!

[Forum-OD-MP]

No.  a VEP will not help you.  a VEP only approximates acuity in a person in which acuity cannot be easily measured.  for instance: a patient who is filing a worker's compensation claim and is faking total blindness...  a VEP can determine if they can see or not.  or another instance:  a person who cannot respond in any way, or if their responses are unreliable like if they are severely mentally challenged, etc.  i think Terry Schivo had a VEP at one point.  and in the case of the last poster who aked about VEP...a patient who seems to have inexplicable/unexplainable vision loss.

a VEP is only reliable to about 20/30 or so.  so if someone told you that your are already 20/20, it doesnt matter if you think you see well or not, a VEP wouldnt help.  plus even if you had a VEP, it wouldnt tell them WHAT TO DO to make you see better, it would only tell them that you either can or cannot see 20/30 (which again is not even as acurate as you have already been measured...you have been measured at 20/20)

just so you know, MOST patients with -7.50 CANNOT read 20/20 thru glasses or the phoropter (machine you look thrugh at the doc's office).  the only way most patients with -7.50 read 20/20 is through contacts.  

a VEP would also not explain anything about MS or neurological probalems at all.

[RunningL8]

I forgot to mention one other factor: I've been told I have mild scarring or an "opacity" on the top of both corneas. No one has been too sure of the exact cause, though blehparitis and years of contacts have been suggested as possible causes. So could that opacity be another possible factor in the acuity problem?  Thanks again!

[Ag-i-doc]

yes, corneal scarring is a known causer of reduced (or perceived reduced) acuity

[Ag-i-doc]

okay so i have to do some backtracking.  a VEP *is* used in the diagnosis of MS.  it has to do with latency of the response between with eye and the brain.  

i wish i could just edit the other response, but i cant.

[sally456]

Hi BG-MN. I have the same vision problems as you.  My left pupil is bigger than my right, and things appear quite not as sharp as with my left eye.  I also have other symptoms. Objects are streaky, like when I move my hand in front of my face. This is more apparent when Im very tired. i also have many after-images and floaters and my eyes get red/bloodshot often.  They both react the same when tested by an opthamologist.  Have you been tested for optic neuritis?
I havent mainly because Im afraid to.  I have had bladder problems too for 18 years, tingling, a liitle numbness here and there, some hearing loss as well.  I was tested 15 years ago for ms with MRI's and sspinal tap. The ms specialist said Ididnt have it. now, because of my vision, Im scared that I do.
I do remeber that after having the chicken pox when I was 23, my one eye became couldy.  The eye dr. thought it was casued by the chicken pox virus but maybe it was optic neuritis.  I do remember him saying though that my cornea has a little scarring from it.  But the opthatmologist i went to 5 yrs. ago didnt see any scarring, or at lease didnt mention it.  If you go to see nero opthomologist please let me know what he says. my email is ***@**** thanks.

[sally456]

One more thing....what is small fiber neuropathy and what does it mean by post-viral?? I wonder if my chicken pox could hve caused nerve damage..also I have bladder problems which started after having a bladder infection.  My bladder didnt feel the same afterwards.  It felt like I had to gp all the time, even after just emptying.  Thanks....

[RunningL8]

Thank to the doctor for the helpful advice.  To sally456:
Even a mild case of small-fiber neuropathy is extremely painful; in my case, I felt like the soles of my feet and the palms of my hands were being pricked by lots of tiny pins.  So it does not come and go, although some days were worse than others.  A neurology exam can detect diminished sensation to things like temperature and vibration, and there are specialized tests to detect damage to the small-fiber nerves. In my case, neurologists ruled out all of the known causes (like diabetes), and they were left with the fact I'd had a virus preceding the onset of the pain. You know, I'm not a doctor, but I learned some things in the very long process of getting a diagnosis, one of which is that one should not try to diagnose oneself! For example, if I looked at a list of MS symptoms, I had several, but really there were other causes, and doctors could tell by the onset and pattern of my symptoms that I did not have MS.  So if a long amount of time passes (like 15 years in your case) and nothing really dramatic shows up, it would almost certainly not be MS. Recently I noticed a similar bladder problem to the one you mentioned; it turns out I have a large fibroid uterine tumor pressing on my bladder (and again, not MS).  So I hope you will get your symptoms checked out rather than worrying.  In the meantime, the best thing for overall nerve function is 600 mg. of the antioxidant alpha-lipoic acid in divided doses daily; this is something I learned from neurologists, and after a year of taking it, my small-fiber neuropathy is barely noticeable.  You can buy it in vitamin stores like GNC.  Good luck!

[sally456]

Can the chicken pox cause optic neuritis...?  Also, do my symptms sound like i have optic neuritis.
I know I shouldnt diagnose myslef, but it seems like I do.  
Also, the opthamologist can check the optic nerve for ON, or do i have to see a specialist (neruo opthaomologist?? I went there about 4-5 years ago soon after the onset of symptoms, but as i said before, I may have had a first bout with it 15 years ago.
The mayo clinic web site said that the chicken pox virus can cause optic neritis...is this only in rare instances?

Thanks!

[Ag-i-doc]

if you had an eye exam, you were pretty much already "tested" for optic neuritis.  ON has a specific appearance that can usually be detected just by looking.  i guess if you had a subtle/mild case it might be iffy, but usually a patient either has it or they dont, and an eye doc can tell just by looking at the ON