It used to be that most gyms set with tape on each hold to mark the route--this allowed them to reuse the same hold on different routes and to use their entire inventory of holds in setting a route, since holds didn't have to be the same color. It also let them solve the colorblindness problem by using patterned tape (i.e. stripes or checkers).

Nowadays most gyms have massive hold inventory and just set routes using holds of the same color with tape only on start and finish holds. It's easier for routesetters, who don't have to tape as often, but I think a lot is lost this way.

You're under no obligation to climb the pre-set routes. You can make up problems using whatever holds are on the wall.

Even moderately competent routesetters will set better routes than are achievable this way. Perhaps if the setting is extremely dense, you'll have enough hold options to come up with some decent routes, but that's work--work you're already paying for setters to do.

I can relate to this. I am also partially color blind and when bouldering without glasses, I so often mess up the foot holds. My partner often thinks I am cheating until I tell her that I couldn't make out the color.

Interesting that glasses seem to help for you differentiating colours?

I guess without glasses everything is a bit worse in general, but they don't really help me see colours better. (But if I got the holds right for my hands, my memory is generally good enough to avoid 'cheating' with the feet not a problem.)

I keep meaning to try giving my climbing partner a later pointer, so they can point out the next coloured hold more easily than with vague descriptions.

There are glasses that, AFAIK, shift the wavelength of incoming light in some certain way such that a colorblind wearer can differentiate real-world colors that they'd normally have trouble telling apart.

It doesn't magically allow colors to show up that they're physically incapable of perceiving, but AIUI it shifts real-world colors that they'd have difficulty telling apart into other colors that they can tell apart, if that makes any sense.

I'm not sure about shifting wavelengths (that seems way too complicated), but you could just block all out the red light on the right eye and all the green light on the left eye, and that would do the trick for someone who's red/green blind.

Maybe, though that assumes they have two fully functioning eyes. I'm not colorblind, but my two eyes can't work together because they don't converge. I wouldn't be able to rely on building a complete image from two incomplete signals; I need a complete image in my left eye in order to see.

Yes, you'd need something different.

Instead of putting these two filters on different eyes, you could put them one after another in time, I guess.

Or you could put a green-blocking filter on the left side of your view (on both eyes) and a red-blocking filter on the right side of your view (on both eyes), and you would move your head around a bit to figure out green from red.

Or you could have a checker-port pattern with the two filters or so.

I'm not sure about straight-up glasses, but there are a few effects you can exploit to enhance hue distinction in the normally afflicted regime (necessarily always at the cost of some other sort of distortion).

The simplest example is just (for red-green colorblindness) red-tinted or green-tinted glasses. You lose some dynamic range and add a distortion across the spectrum, but you gain brightness as a channel whereby you can distinguish many reds from many greens. I used to use strongly orange-tinted glasses to help spot orange buoys in the ocean, which otherwise wouldn't stand out very well against the greenish notes in the water. They'd appear quite bright against a dark background.

A usually less disruptive and less effective strategy is something like what enchroma does. Real objects aren't just red or green. They reflect a variety of rays across the spectrum. If you add a notch filter to remove the light between the two affected cones, green objects will activate the green cones nearly the same as before and the red cones less than before (and vice versa for red objects). That doesn't matter for pure colors like a red or green laser, and it doesn't allow you to see new colors, but it makes most red things a little more red and most green things a little more green, slightly improving hue discrimination (also making some objects nearly black if they hit that notch filter exclusively).

And so on and so forth. Normal lenses won't have any photon upconversion or downconversion or anything, so your only available mechanism is altering the transmission spectrum, blocking some wavelengths more than others, perhaps differently in different eyes or parts of your field of vision. You can give up some other information to add a little resolution to that hue distinction information channel.

With computers in the mix, you can tune that a little better by also shifting hues. Doing so "correctly" is a little hard though. You'd like to do something like just move the problematic wavelengths somewhere else (ideally bijectively, squishing other wavelengths to make room for the displaced ones), but your computer monitor doesn't output a whole spectrum of wavelengths; it outputs mixes of three (three distributions really, but we don't really care). Red and green are two of them, and those are the very things you'd like to distinguish better, so your only real option (realness being measured in ability to help you strongly distinguish red and green) is to add or remove some extra blue (e.g., adding a lot when red dominates green or a little at the other extreme) or to alter the brightness in response to red/green discrepancies. Most OS's want to keep brightness invariant in their colorblindness settings, so the only option is messing with the blue channel. Doing so removes your ability to distinguish some colors relying on the blue channel and adds the ability to tell red from green, with varying degrees of efficacy depending on who coded it and how many details they accounted for.

You could, in theory, have something like a VR (AR? You're augmenting the existing data, but the tech capable of doing that is closer to a VR headset) experience to do a transformation like that on real-world visual data. Maybe simpler when climbing, AR could add stripes or some other distinguishing feature to handholds of a certain color.

Anywho, maybe try sunglasses strongly tinted as the color of the handholds you'd like to spot.

Thanks for the write-up. As far as I can tell, what you are describing in your first three paragraphs is exactly what I was trying to describe? Block specific wavelengths. (EDIT: sorry, I was mixing things up. My comment that I was referring to is https://news.ycombinator.com/item?id=41066579 but yours wasn't in reply to it.)

I don't think wearing any goggles with screens in them is realistic for climbing at the moment.

Yes, adding more distinguishing factors to the climbing holds works. A laser pointer's dot can be seen as a very temporary distinguishing mark.