Sudden incremental reductions in brightness levels while everything else remains normal.

YorkshireMan

Hello,

For many years now, I have sudden events every few months to every few years that suddenly reduce my brightness levels in both eyes at the same time by a small amount, while leaving everything else (visual acuity, colour perception, etc) working normally without any change. The pattern is that there is one distinct event every few years, followed by a series of smaller events in the following months before it stabilises again.

This new brightness level becomes the new permanent brightness level. There is also strong tiredness for a few days after an event. There is no change in my behaviour or activity/eating patterns before one of these event sequences start.

Hospital eye clinics and neurology doctors cannot find a reason. There is nothing obvious in the eyes themselves. VEP tests have not revealed anything. I am due for another MRI but previous MRIs have not found anything.

Things like going outside while pupils are dilated used to be painful, but that has not been true for years.

Has anyone ever seen anything like this before, with just a sudden change in brightness levels in both eyes at the same time (usually overnight while sleeping) without any other detectable changes ? If so, was there a confirmed diagnosis made ?

I am looking for viable suggestions I can run past the doctors in case there is something rare they have not considered, so thanks for any hints or suggestions.

Given the lack of noticable structural changes, I am now wondering if this might be some brain processing or neurotransmitter problem, but I am mostly healthy in other respects, and do things like long day walks (10-15 miles) several times a month without any problems.

YorkshireMan

The comment about dilated pupils is confusing - sorry. What I meant to say is that at my original brightness levels, dilated pupils were painful outside, just like they are for everyone else. However, at the current reduced brightness levels, I no longer feel the same pain when outside with dilated pupils.

BTW, is this the correct section to be discussing this ? Would it be better in the Sensory section ? Also, does anyone know of any more specialist reputable forums where I might get some ideas about suggestions to put to the doctors ?

Thanks.

Albus_Scope

Hi @YorkshireMan and welcome to the community.

Please don't worry about which category your post is in, sometimes conditions span multiple categories.  
I'm afraid I've not heard of anything like you've described, but I really hope something shows up on your next MRI. I'm hoping one of our regulars may be able to offer some advice soon. 

egister

Cataract?

YorkshireMan

No, it's not a cataract, but thanks for the suggestion. Cataracts develop over time, not suddenly in both eyes overnight. They have also been eliminated as a possibility by the consultants.

Rachel_Scope

Hi @YorkshireMan. I'm glad they've been able to rule out cataracts. Are you going for any more tests?

egister

https://forum.scope.org.uk/discussion/comment/884746#Comment_884746

I can assume that the problem is in the visual center of the brain. Try CT perfusion imaging, PET CT.

YorkshireMan

Rachel: I have had another standard MRI (it has been a number of years since the last one) but I do not know the results yet. Not optimistic it will turn up anything however. :-(

egister: those are some interesting suggestions thanks. I will look at them and discuss if they are applicable with a consultant I am seeing next week in a final followup about another issue. (Nothing related to this - it was a tiny retinal tear in the outermost part of my left eye that appears to have developed sometime over the last year without any of the usual symptoms and without affecting my vision in any way. It was discovered during other investigations - I didn't even know I had it. BTW, those lasers HURT but it's better than the alternative. :-) )

One of the most annoying things about this is that it is very clearly something very unusual in that it suddenly reduces brightness levels slightly but permanently without affecting anything else in the vision system, so it is proving very hard to track down as it doesn't match anything the consultants are aware of.