Night vision

Now here’s an odd one.

I’ve never been officially diagnosed with optic neuritis, but had occasional mild distortion of colour vision, which could be a symptom (told neuro, was noted down, but no further action or investigation recommended).

Anyway, sometimes, in the dark, I can see almost nothing out of my right eye. I mean that whereas, with my left eye, I can see a bright rectangle where the curtains are - lit by either street lamps or the moon, as the case may be (street lights go off at late o’clock), and make out the dim outline of the room, and of furnishings, with the right eye, I can only see a very faint paler smudge where the window should be, and no detail whatsoever.

It’s quite frightening to realise that you are - for all practical purposes - blind in one eye when it’s dark (I’m a non-driver, so that bit’s OK).

But the weird part about it is: “sometimes”. And I don’t mean for a few days or weeks in a row, as in a relapse. I mean for just half an hour or an hour.

For example, just after lights-out last night, I noticed night vision in my right eye was almost nil. I experimented closing first one eye, then the other.

Left eye: reasonable but dim view of the room. Clear definition of where the window is. Right eye: no visibility of the interior of the room. Pale smudge in the direction of the window.

Eventually dozed off, feeling a bit depressed/frightened (though this has happened before), and telling myself: “Well, if it’s damaged, it’s damaged - it’s not as if you have a problem during the day.”

Yet woke up about an hour later, and found, to my amazement, that although right eye vision was still inferior to the left, there was now much less difference between the two, and each eye could (independently) see the outline of the window, and make out features of the room.

So it’s almost as if the right eye does have night vision, but is very, very slow to switch to it - i.e. takes an hour to notice it’s in the dark,but adapts eventually.

I don’t think ON would toggle on and off like this - especially in as little as an hour - but I stand to be corrected.

Otherwise, is there a name and explanation for this: “eye slow to notice it’s dark” kind of thing?

As I say, it’s not the first time it’s happened. I think I first noticed it pre-diagnosis - so more than five years ago (and I’m not blind yet). But I had the same confusion as now: at one point in the night, the eye couldn’t see, or just barely. But later the same night, it had recovered to almost as good as the “good” eye, so I wondered if I’d dreamt the whole thing.

Can ON be so variable over such a short timescale?

Is it some kind of fatigue, and sleeping for an hour fixes it?



hi tina

when i wake up in the night it’s in response to the demands of my bladder, so it’s always emergency mode.

i haven’t been as scientific as yourself but i can find my way in the dark by feeling for the wardrobe and then trusting on memory of where to go next.

i was terribly worried at the prospect of ON at first therefore made myself practise getting to the loo without being able to see.

fortunately (touching wood) i haven’t had ON yet.

i have had a mishap when i tried getting back to bed in the dark - i walked right into the stairwell wall!

my head made such a thunking sound!

hopefully someone with a scientific leaning will answer your question properly.

carole x

that metaphor of dancing when needing a loo makes me think of “dancing in the dark”.

so my toilet adventures in the early hours are made to a mental soundtrack of bruce springsteen!

Tina, I think that reduced/slowed dark adaptation is one of the things that optic nerve damage can do. Worth a web search, perhaps.


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Hi Tina,

I’ve had this once. I turned off the light and the vision from one eye went pitch black & could see nothing I panicked and turned the light back on to check I could still see which I could instantly.

When I turned the light out the second time my eyes were fine. I have been told my optic nerves are fine.

I have had 2 occasions of issues with blurred vision in one eye but they were after getting hot. It’s always my left eye.

Snowqueen x

Hi - conc. night vision, I had ON last year in left eye. Never recovered my sight and find functioning in the night has become near impossibility

Hi Tina,

this is exactly what I get and I have had ON 3 times in my right eye. For this reason I don’t drive at night especially on the motorway or country roads as I can see anything because the lights from oncoming traffic confuse my eyes too much!! Luckily my left eye is fine so I can stumble around at night x

had a few clunks too though Carole!!

Stacey x

Hi Tina,

I have this as well. It first happened during a period of eye pain so perhaps ON, although like you I’ve never been diagnosed with ON.

It only happens when I turn the light out and only every now and then now, but it’s almost like one pupil is slower to react to the change in light than the other.

As you say, very scary the first time it happened.

Hi. I was dxd with RRMS at the beginning of the year. My problems started kicking off last summer, when I had a posterior vitreous detachment in one eye (as I was lying in bed one night I saw a sort of golden thunderstorm in my left eye). I went to an eye specialist and was told that this was what it was but fortunately the retina hadn’t detached. I then had a few other problems which led me to the dx of MS.

My eyesight is still affected and the neuro thinks it’s due to lesion on the optic nerves.It’s annoying though as it comes and goes (like all my other MS symptoms, so at least I can say to myself ‘well, tomorrow will be different’!) I manage OK, and I drive, but I avoid driving in the dark unless I really know where I’m going. I would describe the feeling like always having dirty lenses in my specs - I lose count of the number of times I clean them - although they do get smeared a lot! I have a very good optician and in fact I’m just having my lenses made up to a stronger reading prescription. xx

Thanks for the replies, all.

It seems I’m not unique at least, and whatever the exact mechanism, it’s probably to do with MS.

Alison, yes - without having done any detailed reading (yet), it does appear that reduced or delayed dark adaptation can be a symptom of ON, but is also common with ageing, in people with otherwise healthy eyes. So I can’t be sure it’s not just getting old.

But I could understand a delay of a few seconds to adapt - this is much longer, to the extent you have the impression it’s permanent, and it’s only when you’ve diverted attention from it, and done something else (typically sleep!) for quite a while that you notice it seems to have corrected itself.

Snowqueen, it’s especially as you’ve described - i.e. turn lights out: “Panic, panic! I’ve lost the sight in one eye!”. Turn them back on, and no problem presents itself - all seems quite reasonable and normal. My eyesight without glasses is pretty poor anyway, independent of MS, but certainly adequate to negotiate a room in natural or artificial light - not good enough to see the fine details of ornaments, or the patterns on decor, but certainly to recognise (and avoid) major obstacles.

But the intermittent night vision loss - although thankfully only in one eye - is so profound it’s genuinely surprising I can see again with the light back on, because I never expect to. It’s always a relief and an amazement to find nothing amiss. Turn the light back off, and the eye is almost blind once again. No discernment of shapes at all, and only the faintest glimmer where the sodium-glow of the window ought to be.

Carole: I do have mishaps going to the bathroom (not wetting mishaps), both night and morning. But with me, it’s balance more than vision. When I first stand up after being in bed for some time, it takes a while to get my land legs, which means my first trip to the bathroom is always wobbly. Although I’m not a large lady, and can see full well where the doorway is, I somehow manage to misjudge and hit it - usually at the shoulder. Then quite often repeat it on the way back out, but the other shoulder, so at least end up with symmetrical bruising - how attractive (not!)

I’m one of the few people (though not few among MSers, I suspect), who can use that suspicious excuse: “I walked into a door!”, with complete honesty, and without meaning: “My partner beat me, but I’m not going to tell you.”



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my husband has told me sternly to stop being so flippin clumsy because people keep asking him if we are having relationship problems!

at least i know that people around here have my back!!

i have never had so many bruises.

my thighs are patterned with them due to the corner of the dining table.

shoulders from bumping into things.

well hey…

carole xx