Do night driving glasses make it easier to see at night?

Question

There are many yellow-tinted driving glasses being sold with claims like this one:

• Yellow lens tint enhances contrast at night
• Anti-reflective coating reduces glare.

There are also many posts like this questioning the effectiveness of them

Night Driving Glasses May Hurt, Not Help

But do night driving glasses work? Ophthalmologist Andrew Iwach, MD, isn't so certain. He discusses his doubts in this ABC news segment.

What concerns Dr. Iwach is that the tinted or polarized lenses used on so-called night vision glasses are designed to limit or reduce the amount of light getting to the eye. Anything that does this at night will actually make it harder to see, not easier, according to Dr. Iwach.

Do night time driving glasses make it easier to see at night?

Answer 1

Personal test experiment, (more of an extended comment than an answer)...

Sometimes I have to drive a four door sedan at night, during times of sporadic traffic, in a town with curvy roads and hills where about half the cars on the road are SUVs, and half of those never seem to turn off their hi-beams. SUVs are taller than sedans and have headlights at about the same level as both the front windshield and rear window of the sedan: the resulting glare is more severe than if all the other cars were sedans of the same height. On a straight road the oncoming hi-beams needn't be so blinding, (one can look to the right), but on a curve with an oncoming caravan of hi-beams, (or worse, a curve on the top of a hill), looking to the right means the lights from the cars in back of the first oncoming car will still get you.

Until recently I've been using the squint method to cope with the above conditions, which is to squint the left eye closed when there's oncoming traffic, using the bridge of the nose as shade to one's open right eye which accommodates itself to the glare. When the oncoming traffic ceases and the right eye has momentarily lost its night vision, (a few dangerous seconds of blindness), open the left eye, which still has its night vision. This method works, but it's stressful, and it feels like a huge relief when the trip is over.

A few months ago, wishing to experiment, I bought a cheap $10 pair of these yellow night driving glasses at a local CVS, and have been using them while driving at night. Observations:

• The glasses certainly don't help me see more, that is, I can't see any more detail with them than without. It's not like those before/after pictures used to sell the glasses.

• The glasses' yellow tinting appears mild, so that at first it seems like it should have no effect. To the degree that the shading blocks light, there's not a noticeable loss of detail or light, excepting the yellow tint which one soon gets used to -- perhaps since less light gets in, the irises dilate more to compensate.

• No improvement in reducing disability glare. Oncoming headlights still make it it just about as hard to see things.

• Large improvement in reducing discomfort glare. Oncoming headlights do not hurt or cause the same stress with the glasses on. It's rather like the difference between looking up at the sun, (which hurts), and looking at a photograph of the sun with some surrounding landscape -- in the photo there's still all the glare, but it doesn't hurt to look at the photo.

• Immediately after the oncoming headlights are gone I can see fine with both eyes, without an adjustment period -- that is, there's none of the loss of night vision that occurs without the glasses.

• So the squint method isn't necessary with the glasses, and both eyes stay open.

• When the trip is done, it's a mild relief to stop. The night driving experience is very noticeably less of an ordeal.

Summing up: with respect only to vision -- the glasses don't make it easier to see when there hasn't been any glare; nor during periods of glare, but right after being exposed to glare the glasses make a positive difference. With respect to pain and stress, the glasses make night driving less painful and less stressful. Whether wearers of these glasses are not obliviously driving more recklessly with the glasses on, (like confident Mr. Magoos...), seems less obvious, perhaps another answer can turn up a more general overview.

Answer 2

There is some fairly old research suggesting that night-driving glasses, i.e. glasses with tinted glass, do not make it easier to see at night, and might even have a detrimental effect. Both acuity and contrast appear to be impaired (note: with the exception of the first paper by Lauer et al. 1949, I'm going by the online summaries, as I currently don't have access to the full-text publications).

Lauer et al. (1949) find that despite subjective preferences for this type of glasses,

filtering lens reduces acuity in low-level illumination

and warn that

[s]ince evidence from various sources indicates that night driving is more hazardous because of insufficient illumination, anything which further reduces seeing efficiency is not to be recommended in the present state of knowledge.

Similarly Richards (1953) also finds that night vision does not improve by wearing yellow glasses. On the contrary,

A small but statistically significant loss of vision occurs from yellow glasses. [...] No observers showed any consistent gain in seeing with yellow glasses for both acuity and contrast for all luminances tested, although random small gains were common.

Concluding, he also advises against using them:

the loss from yellow glasses is potentially dangerous and the data recommend that yellow glasses not be worn during night driving on public roads.

Apparently, the detrimental effect is not restricted to yellow-tinted glasses. Miles (1954) argues that

the use of tinted glass in automobiles is dangerous because of decreased visual efficiency at night. Under night-driving conditions the visual acuity is 20/32 on Snellen type through colorless. Light-yellow night-driving glasses change this to 20/34. The second shade of pink glass reduces visual acuity to 20/40, while while the green windshield glass reduces it further to 20/46.

To answer your question: I couldn't find empirical evidence that night-time driving glasses make it easier to see at night. On the contrary, the research that I could find suggests that wearing these types of glasses makes it more difficult to see at night.