We All Get Low Vision Sometimes

What We Can Learn From Not Seeing Things

All of us experience the annoyance of not being able to see things properly, or at all. Sure, that’s not technically ‘Low Vision’, but it’s useful to consider those situations, as it can provide insight when we have patients whose vision is inadequate for other tasks. Consider them ‘lessons in empathy’.

It's Too Small

This is a microfiche reader. There are probably a lot of (younger) readers who have never encountered one. In the days before extensive digitisation of resources, libraries would deal with the problem of storing vast quantities of newspapers, magazines and other documents by taking very high resolution photos of them, and then storing the miniaturised slides of those photographic images, which took up only a fraction of the space.

The reason I’m showing this device is that those images were truly tiny, each page much less than a centimetre high. There was no way our eyes could see such fine detail, so we used a microfiche reader to project a highly magnified image of the slide on to a screen. This was how we dealt with encountering detail that was too small — we used a device that made it bigger.

This is an extreme case, but we’ve all encountered unreasonably small legal fine print, or a splinter in our finger, or an interesting but tiny insect.

It's Too Dark

We all know this one. When what we’re looking at is too dark, we find a way to make it brighter. Lighting design is all about making sure we have adequate light in our day-to-day lives, but our standards are calibrated around normal vision.

As soon as the light levels drop to a point that we are not seeing comfortably, our first response is to seek extra light. We turn on the room light, or move to a brighter spot, or bring a light to whatever we are trying to see.

It’s worth underlining here — we almost always reach for a light, not a magnifier.

It's Too Faded

Historians often encounter faded documents, which can be of great historic significance. For the rest of us, probably the most common scenario is a faded receipt, which can be very significant in its own way.

Sometimes they are so faded they seem impossible. To read them, we need the big guns — a magnifier might help a bit, and bright light might help a bit, but what you really need is a computer that can photograph the image and then enhance the contrast, creating a substitute image that is easier to read. That is, we make the print bolder.

We encounter less extreme examples all the time, in the form of food packaging or magazine articles that use dark print on a dark background, or light print on light. This is just careless design. An important part of inclusive design involves avoiding low contrast whenever possible, even if it looks arty/cool.

I once attended a lecture by a world-renowned glaucoma specialist. He illustrated some of his charts with labels in yellow text on a white background. None of us could read it. I was amazed that he — an optometrist — could make such a careless design choice.

There's Something in the Way

It’s hard to get real insight into what visual field loss is like, but consider these:

We’re all used to not being able to see things that are behind us — we need to turn our heads (scan) to bring them into view.
If we are at the cinema and a tall person sits in front of us, we might not be able to see the entire screen in one go, no matter how hard we try. We have to keep shifting our head from one side to the other, trying to build up a composite view of both sides of the screen.
If there’s a person standing behind some foliage, we might be able to see they’re there, but the branches and leaves get in the way and make it hard to recognise who the person is.

In all of these situations, our response is to move, so the obstacle is no longer in our way.

There's Something in the Way — and It Moves When I Move

What happens when we can’t move to see around the obstacle?

The one we’re all familiar with is having an annoying afterimage from a camera flash or the reflection of the sun, temporarily giving us a blind spot that moves with our gaze, everywhere we look. There’s really nothing we can do about it other than wait until it goes away.

That afterimage is probably the closest we ever come to the annoyance of a macular scotoma (blind area). But it’s different in two important ways.

It soon goes away. People with macular scotomas are stuck with them.
We can see it, whereas with a macular scotoma the brain tends to fill in the blind area with its best guess, so people tend to see it as either a blurry area or just not be aware of it at all (other than noticing that things ‘jump’ in and out of view).

How do we deal with it? It’s hard, it’s not something you can just use a light or a magnifier to fix. You have to try to work around it — for instance, you might see a thing better by looking just a bit to the side if it, instead of directly at it.

Starlight Macular Scotoma

You might remember, way back when we were discussing the retina, that the rods are the photoreceptor we use to see at very low light levels, but there aren’t any rods at the fovea. So when we are looking at the very faintest stars at night, we will see them more easily if we look just a tiny bit to the side of them. Effectively, we all have a tiny foveal scotoma in that very low light situation.