I think that the LED lighting already caused the population vision to degenerate, because it causing people to prefer brighter lighting than usual and to not seeing good with lighting that was once enough.
In the past, street lighting with <125W MV lamps was enough for safety and now it is too weak.
I can see this phenomenon at the entrance of Carmel hospital, where when I turning off part of the LED panels, most people says that the lighting is insufficient and turning them back on.
Also: Most LED streetlights at Kiryat Ata, are brighter than the former HPS streetlights.
Your opinion?

Your observation is not related to LED lighting, but to 2 other things :

1.
The cause of complaints in your example is you switching off the lighting, not the absolute light levels

2.
Many people want brighter lighting than minimum, sometimes really excessive, sometimes just somewhere above he minimum levels but reasonable. In any case, bringing 125W Mercury lanterns as example ignores 3 decades of HPS and MH inbetween

I don't think so. The Netherlands has a culture in which people often leave their curtains open at night so you can look in. It's still as dim in the evening as it always was. The only change is that there is more variety in color temperatures.
In the incandescent and CFL times, everything was 2700k, with the odd 4000k halophosphate kitchen light visible. Today, i can see mostly 2700k, but with a bit of 3000k too, and 4000k has gotten more common. Now we also see (rarely) 6500k.

Laurens :
The culture here is different. It is very diverse, some people have preferences similar to what you describe, some entirely opposite

I can confirm that there are more people here who will call anything other than 1000 lux 6500K in their living room "bad lighting"

Those existed as far back as i can recall since young age. In the 90's that would be 160W MBFT's in a nice 5 arm chandelier (that one was in a big room of an old house), in the inbetween years that would be with grow-light size CFLs still in the same chandelier, and nowadays it is equivalent light levels with awful flat LED panels



LAB27 :
There are people with 6500K setups, both those who are excessively bright (what we have been discussing here), and who are dim to normal. The latter ones became clearly visible with the CFL boom in the early 00s and now LEDs, but they always were out there, even in the old days with plain 1x20 Fluorescents

Many people, especially in the "i want very bright light" camp, judge the quantity of light by the visible glare from the luminaire and not by the actual light levels resulting in the area. LED luminaires are at the absolute top by glare, so they always appear "good"

In road lighting there is an additional factor : LED luminaires are very highly optimized to make uniform light levels (low Delta) along a theoretical road with perfect luminaire positions

First, "lens panel" optics emit legendary amounts of glare while directing the light to achieve this uniformity (which isn't even required to see well under the light). See reaction to glare above

Second, when the terrain is not an ideal straight road and luminaire positioning is a bit ad-hoc (as it is in virtually all of Hadar for example), the pattern put out by those LEDs will cause over illuminated spots to really stand out, something which is not so obvious with HPS

Color temperature is very strongly correlated to cultural background here. In row homes where families are mostly from western european descent, 2700k.
In apartment blocks, where many of the turkush, morroccan and middle eastern people live, you'll find 4000 and 6500 more often because of the apparent correlation between living near the equator/in a very warm country, and wanting a cooler shade of light.

Always been like that only in the pre-led days, their only choice was 4000k circular (kinda rare) or linear fluorescents in the living room. CFLs we didn't have in 4000k, unless you went for PL but at hardware stores all PL fixtures were meant for outside use. So only the die-hard fans of cold white light would have a brightly shining fluorescent right in their living room.

The fact that lots of people judging the intensity of LED lamps by the glare of it, proves my thoughts about degenerate of the vision of people.
Also: My brother and my father and my mother all preferring >6000K, because they saying it is brighter than 2700K, and my mother because she don't see well with <4000K light.

The judging of lamp brightness by its glare is not result of damage, but simply of the appearance of high glare LED light sources, everywhere where the previous sources were not as glaring :

 - Flat panels with flat light distribution replacing highly directional reflector modular luminaires (4x18W)

 - Floodlights lacking any optics whatsoever replacing way bigger in size HID floodlights which did have optics

This had been going on, and actively abused for sales and promotion, since the earliest days of high power LED lighting, so way before anyone had the time to get vision damage

With additional vision damage the demand for bright light (which tends to correlate with being 6500K, probably to compensate for the degraded S cone cells) will remain the same or increase

Your mom is on one end of the scale, where for many it is the opposite effect. Of those who want bright light like your mom, i wonder how much of it is attributed to actual vision damage (whether from LEDs or just from age and other health factors), vs. how much when actually seeing the same "picture" as me (for example) but claiming that it is not bright enough, in the same cases where i would consider the light level adequate

Higher color temperatures are associated with higher visual acuity, so your mother is right in noting she can see better with that kind of light. Just like with your hearing, your eyesight also can slowly degrade as you get older. I am 35 and still can do fine without glasses, but my parents and grandparents all needed some form of glasses at some point in their life.

I have noticed it myself. I used to light my old bedroom which doubled as electronics workshop with a 40w or 60w bare incandescent in the ceiling. When i switched to a long life incandescent with roughly the same light output, i felt like i couldn't see properly anymore. Those long life things run at a lower temperature so you get a lower CCT. With a 60w longlife i could see less than with a 40w normal one.

For me personally, any higher than 3000k doesn't feel like it has any benefits as workpiece lighting. In the lab at work we have color 830 fluorescents (for now, they'll be ledified in about a year's time...) and 6500k feels like i can't see colors properly anymore unless the light is particularly bright and of a higher CRI than your bog standard LED has to offer.


With regards to glare - how do you define it here? Reflected light from a wet road, or the visibility of the light source in your periferal vision?

Glare is defined by the surface brightness of the light source.

So you and Dor's mom indeed represent 2 opposite ends of the "spectrum" of people's reaction to light sources CCT, and possibly light levels



My own light preferences :

To me proper indoor lighting is mostly the spectrum of Fluorescents. I do well with most FL from 640 to 765 and from 827 to 865. Some of the 827 is a bit borderline in terms of color preference (too pink), but in terms of seeing is ok. (827 varies a lot between manufacturers and lamp types, i noticed that most PL-type lamps 827 looks much better than what's typical for E27 CFLs)

For general area lighting my light levels are low. 11W/840 PL-S (and possibly with an opaque lamp shade that may reduce the level a lot) is sufficient to light a 3x4m room, and a few and far between 36w/765 T8's light up my workshop

On the electronics bench i do use more light. Currently in my workshop desk there is a 2x80W/840 T5 above the desk, which is over the top in light levels, but does indeed help looking at small SMD stuff

Incandescent/Halogen while i can see well, i would like a bit higher CCT. (Here 12V Halogens are indeed a little better)

LED anything >2700K does not look right - it appears to be deceiving in color rendering, and >4000K also makes for noticable extra load on the eyes. Not usable in any long term general or task lighting. No such problem with any FL, up to and including 765 and 865

LED 2000K (got a couple of those "vintage" filament lamps with gold-colored glass) does not look too bad, in particular because it does not appear to be trying to look like a white light source. It is "explicitly" a color light, its blue light content is as low as can be for a "blue and phosphor" LED



However, one setup with LED i installed very recently - a dark outdoor place around the workshop, where i installed lighting on a staircase timer (controlled by buttons from 2 ends from which you can walk there). Lamp is a 20W 1800lm 2900K snow cone in a white plastic posttop moon balloon lantern. It switches on to immediate full brightness, it won't melt a hole in the lantern if let to run for too long, and its life probably won't be cut short by the frequent starting

It is borderline in terms of preserving night vision (if i look under its light and then into the dark wilderness around), though being just 2000lm, in a 300mm moon baloon, on a 4m pole, its effect is minimized

I might convert it to Incandescent if i choose at some point to change to a metal/glass lantern, eliminating the risk of melting, but for now let's evaluate the setup as it is



I think the real definition of glare is by the perception of glare, which may involve quite some quirks of how our vision works. I think it comes down to 2 things :

 - Relation between brightness of the light source seen in the peripheral vision vs. the areas that are intended to be illuminated

 - Relation between brightness of the light source seen in the peripheral vision vs. the background area visible behind the light source

Reflected brighter areas from a wet road surface - I would intuitively not define it as glare, unless it is extreme. Maybe as non-uniformity in the appearance of the road ok, but then i think all the big rush for perfect uniformity is BS anyway, uniformity does not lead to better visibility