3. Duck Tape Specs


Some glasses that can live with a little temporary gunk on them.

Duck or masking tape.


At a recent Stroke Association meeting we discussed what we can do to offer people a window into the experience of stroke survivors. For example how could we simulate what it feels like to lose the use of an arm? Or what vision loss caused by stroke might be like?

Vision loss from stroke is most commonly ‘homonyous hemianopsia’; loss of the right-hand (or left depending where the stroke is) field of vision in both eyes. I know there are special glasses to simulate this. But can we do something simple as part of 101 Experiments? Yes.


Tear off two strips of tape, each enough to cover half of each lens of you glasses and stick them on the left hand side of each lens. I found this a bit confusing to get right (and also needed a second pair of specs to see what I was doing). Here’s what your ‘hemi specs’ ought to be like.

A pair of spectacles with the right-hand side (from the wearer's point of view) blanked out by tape

When ready pop the specs on and look around the world. Do some reading. I guess it will be a bit of a strain.


This is really quite a good simulation of right hemianopsia. Viewer: I have this condition.

I was wrong to be skeptical. It’s not perfect, nothing can be, but this simple experiment is likely to get as close as any more complicated simulation.

Notice that it feels the problem is mostly in your right eye, although the artificial impairment is to both. This is exactly the subjective experience of hemianopsia patients. Vision on one side has been lost in both eyes but the feeling is that the problem lies only in the eye on the side affected.

Next experiment

The next in the series, 4/101, will be ‘Frostie specs’ .


About partialinsight

One evening I had a stroke. Half my sight vanished overnight. Adapting made me grasp how amazing the visual system and brain are. It also taught me to understand disability completely differently and I'm grateful for the lesson.
This entry was posted in 101 experiments in seeing, Blindness and visual impairment, Stroke, Disability, Cognition, The brain and visual perception and tagged , , , , , , , , , , . Bookmark the permalink.

3 Responses to 3. Duck Tape Specs

  1. Stephanie says:

    I haven’t tried this experiment, but you’re right, it’s important to find ways to try to show others how you are affected. I know there were some workshops for MS to explain how some symptoms feels: like trying to make oneself some tea wearing some gardening gloves to explain the loss of sensation in hands and how everything becomes harder, same thing but trying to lace your shoes, or fasten buttons. Wearing wellies full of sand to feel how hard it can be to walk then, I think there were a few eyesight experiments, related to lack of balance as well. It is a great way to show others what’s every day life can be when you live with it full time.

  2. Ah those are all good experiments.

    I think this sort of thing is so important so people can begin to grasp what symptoms are like, and to get inside the other person’s skin. I think the Stroke Association have used a special sleeve or something like that to simulate having lost the use of an arm.

  3. Very good post. I will be dealing with a few of these
    issues as well..

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