Hey Went for VEPs today. Left eye is bad at mo, very blurred vision for 4 days now and painful eye socket. When lady tested right eye she said look at the red square whilst the black and white checkerboard moves around in the back ground. When she tested my left eye (the bad one) she told me to look at the red square. now the square was not red it was blue! I told the lady the square was now blue and she kept saying it was red! I assured her the only coloured square on the screen was BLUE and did she want me to watch the BLUE square? So we agreed I would watch the blue square. Now obviously I have an issue currently with colour blindness in my bad eye and blurry vision. Which i was completely unaware of. But this is not always the case most of the time my eye is fine. Never notices the colour issue before. It was just pure fluke that the test was during an episode of dodgy eye ball lol. Also when she tested my left and right eye reading a board with letters on I noticed the whole room was a different colour with left eye! It was washed out and almost brown/ sepia tones! Again never covered one eye before so never noticed lol. Any ideas rizzo or anyone as to why I’m seeing blue instead of red? And do you think it will affect my results of VEPs? Thank you for reading Jojo xxx
It sounds like you might have optic neuritis - it commonly affects colour vision, especially red.
Why you’re seeing blue instead of red is basically because red isn’t being processed properly. There are two steps in colour vision. The first is a simple detector set up in the eye; there are three types of detectors: red, green and blue. The next step works more like see-saws. There are two: red/green and yellow/blue (yellow is a combination of red and green - colour vision doesn’t work like paint!). If red isn’t working very well, then the signal that gets through to the second step swings the see-saws towards green and blue. And that’s what the brain tells us we’re looking at!
You know how we can see blueish red, but not see greeny red? It’s because of those see-saws: they will not process red and green together - it’s got to be one or the other! So why did you see a blue square and not a green square if red isn’t working properly? I would guess that the red square was actually a blueish red square - so light with a lot of blue in it. Take away the red and the blue signal dominates, and so our brain tells us we’re looking at something blue.
Did that help?!
Will it affect your VEP results? If you have ON, then yes, almost certainly. But that’s why you were having it done - to see if there is anything going on with your vision. Pretty good timing really!?!
It would be worth seeing an ophthalmologist to get it checked out properly so please go and see your GP and get a referral.
I hope it settles soon.
Karen x
Thanks so much Rizzo I appreciate your help. Although the whole red/ blue argument with the nurse was quite comical your absolutely right - the timing is impeccable! How weird that this vision issue came on 4 days ago and is still present today. Also I’m having a brain MRI tomorro could the fact that this is happening as we speak affect those results too? Should I ask for contrast? Or will that have been decided? I’m wondering wether this bout of ON or whatever it is will also assist MRI results as it is occurring right now? What do you think? Jojo xxxx
It would be worth telling the radiographer about your possible ON. He/she may be able to ensure that your optic nerves are sufficiently visible, although I wouldn’t bank on it (it requires knowing what to look for, checking the images and then redoing a scan(s) with the scanning area adjusted as necessary). Getting an ophthalmologist’s diagnosis should be sufficient evidence for your neuro.
Contrast may help any inflammation on the optic nerve stand out, but it will only help if the slices are thin enough (because if they aren’t, you’ll struggle to even see the optic nerve).
I don’t know how much authority the radiographer has about whether or not to use contrast, but you could always ask. Make sure and make it a question “ON…someone said…what do you think?” because they are not always terribly receptive to a non-medical person challenging them!
I hope it goes well.
Kx