25 mph is already pretty darn slow for a descent. And it's not just descents. What about windy days? What's the OP going to do? Not be able to ride into a headwind because he can't see where he's going?

Ooooh-kay.

The OP didn't write anything about a problem with windy days, or that he was in a race, but did mention he didn't care to unnecessarily endanger himself when going over 20mph. Are you suggesting he ride as fast as possible at all times because that's what all the Real Cyclists do?

Problem solved by switching to Casco Speedairo (or Casco's other models that takes its eye shield) helmet with its eye shield. Tears have gone and now enjoying a panaroma view.

The eye shield wraps very well. The helmet has many points which you can adjust the fit to suit your head and contour of your face. Choose the coeect size will do.

I got a pair of safety glasses that resemble sunglasses. I got the transitions lenses in them, too. They were fairly cheap because my glasses shop sells the safety glasses really inexpensively.

A good size pair of prescription sunglasses helps. The lenses don't have to be huge.

I realize that it looks real geeky; but I wear a pair of goggles that fit over my glasses in the winter.

Yes, particularly in cold weather. I find wrap-around sunglasses or goggles help.

Yep, I've worn glasses all my life, and know this issue of watery eyes well, too. Also, my eyes are really sensitive to harsh sunlight, or glare. I just wear the old-fashioned "clunky" aviators, with the lenses that are clear in normal indoor lighting, but darken into sunglasses outdoors. I sometimes think I need goggles for over them, in the winter, but I usually just keep a finger of my gloves clean enough to wipe my eyes, as needed. ;) One of these days, someone will invent a proper fix, maybe a heated helmet visor/windshield thing-a-ma-bob. :D

I squint or blink really hard. For something different I wonder if any kind of eye drops before the ride would help. It seems it is the wind drying out the eyes causing them to tear so if some fake wetting drops may not dry so easily, idk never tried it. I was thinking mtb helmet with goggles. Squinting before they get too teary may help too if you know its coming.

The resurrection! The SpeedAiro is dope, tho. I have both a Dux Helm and a Giro Air Attack, but I still want a SpeedAiro in the mix.

I went to contacts and large cycling glasses in part because of this. Especially in cold weather.

I wear contacts... ONLY when cycling... and the wrap-around, hug your face, cycling glasses with small vent holes. The cycling style sunglasses does the trick 90% of the time. But in the winter months I need to wear my goggles or the cold will suck the tears from my eyes.

Then there is... this time of year. When the trees are in bloom and the pollen count is through the roof. My eyes are sensitive enough when I wake up, let alone speeding down hill.

Sometimes... the solution is just to slow down.

Oakley Rx glasses here. Wish I had done it years ago.

I had Rudy Project sunglesses when my eyes were better. Loved them.

Any good quality cycling glasses would surely help the OP.

Watery eyes and eye irritation often begin with the nose. Irritation to the nasal passages and sinuses can provoke eye irritation and watering. You might be sensitive to dry air -- cold or hot -- and road dust, etc.

Try wearing an ordinary surgical/health type mask for a few rides and see if it helps. I've occasionally used the types with elastic that wraps behind the ears. Helps keep the nasal passages from drying out, and filters out some road dust and allergens.

BTW, this is the same cause for onions causing stinging, watering eyes: breathing in the vapors from freshly cut onions. Pretty much any simple mask that screens out some of the vapors can help. But I just keep the onions in the fridge and use an ultra-sharp knife, both of which reduce the airborne vapors.

Too much wind sucks the moisture out of my eyes so last night I ordered moto-x goggles. Waiting patiently for the brown santa to deliver the item.

I wear contacts and wear just regular wire frame sunglasses. My problem with the sport wrap around glasses are they all seem to have straight arms that dig into the side of your head. That's instant headache for me.

I like bronze/copper color sunglasses and polarized. I'm not sure if I can get a pair of safety glasses tinted like that that don't have the headache inducing straight temple arms. I haven't really looked, but I doubt I could get them polarized.

So, I just put up with the tearing up eyes.