Two surprises with glasses

^{That's what happens if you hit the glass with a hammer, but about that later}

A little more than six months ago, I was suddenly struck for good glasses. I started asking the same stupid questions and getting different answers. Who do not ask about anything - their technology is the best in the world. However, after the words "justify, please," problems with proof begin. In the end, the road of adventure led me quite far away.

So two important points. First: it turns out, it is necessary to make a full correction, partial - in most cases, evil. The proof that “they have not done this in Europe for a long time” did not suit me, so I had to dig research. The second point - the fucking light filter "for the computer", which cuts the blue one, is still needed. But only, it seems to me, not for the computer. There were also results, but on animals.

Full or partial correction

In our story, it was assumed that if you have -3 , and you wear glasses -2.5 , then your eyes will do your best to correct myopia. And at least she will not progress. Opinion is very common - for the past 16 years I have worn glasses precisely on this principle. If you ask the question "why," then the interesting one opens up. It turns out there is a basic study on shrews and chickens. He was not tested in public. And based on it, they started doing such things with glasses all over the world. Chickens - Schaeffel et al., 1988, F. Schaeffel, A. Glasser, HC Howland.

A little later, even in 2001, Uncle O'Leary wondered if it worked in public. Here is his research , which became the starting point for other similar ones. Kolupaetsya further, we find the review material in New Scientist (with charts), 2002. In Russia it was repeated in 2010, 62 students (48 students reached the end of the study):

“The rate of progression for the two experimental groups, expressed in diopters for the year, was 0.55 D / year for the group with complete correction and 0.66 D / year for the group with undercorrection. These values ​​are higher than the results obtained by Chung, Mohidin and O'Leary (10), which amounted to 0.38 D / year and 0.5 D / year for the groups with complete correction and undercorrection, respectively.

“Our results revealed a trend confirming the fact that it has already been established that under correction of myopia at the initial stage is not a successful therapeutic method for the prevention of myopia, and that a complete correction should be used to correct myopia.”

The point so far put Minaev in the "Bulletin of Optometry" in issue number 1 for 2011 year. He brings a lot of research and shows what the Chinese have done with different new forms of lenses. The result - undercorrection is not needed. Next door in the same issue, Jean-Pierre Laguier tells about the same thing about the results of Canada. I was provided with photocopies of these journals — contrary to the twenty-first century, these things still come out in paper. Because one of the copiers is very greedy and is still alive.

But to the point. The main question - what threatens undercorrection. My source, Uliana Dyadina, Nikon's doctor, said that a long undercorrection causes problems with accommodation. Up to the latent squint. Therefore, further we spent almost half an hour to understand how much I suffered. It turned out pretty unpleasant. The result - instead of glasses with a flat correction, she proposed to make a tricky version of the progressive ones - in the center is a complete correction, to the edges it decreases so that the eyes are accommodated. It was supposed that it would help me when working with a computer, since it is close. About the result I will tell a little below. He, contagion, controversial.

What are the glasses made of?

In fact, one of the purchase triggers was that I wanted polycarbonate lenses. I once had my glasses cut with a katana, and part of the glass was poured into the eye. As a result, they made me nifiga not polycarbonate, but another plastic, the name of which they did not pass even after three requests. With glasses they gave two demo lenses from the same plastic, and I did a little crash test.

First, a little drilled. The shavings fused into clusters have fallen: it seems that I have heated the plastic more and scooped it out of the hole.



The burr in the center of the hole froze and remained standing, but could not be torn off.

Hit with a hammer:



Large fragments were formed, with the edges of them stupid, you can safely drive with your finger, nothing will happen. No small details (what is seen on the frame is chips from previous experience). Here is a chip after the first strike:



The following experience went to my glasses, which I did in Astrakhan immediately after one of the fights, in which the previous ones heroically died. I realized how good it was that I first hit the cheekbone, and they flew off. Because in the experience, I hit them with a hammer and just screwed on the rain from a small glass crochet. Well at least, the mind was enough to beat in the package:



Each fragment is sharp here, and the fragments themselves after the impact are clearly more than a couple of hundred. It seems that now I trust the plastic.

Enlightenment, anti-glare, antistatic, hydrophobic coating, oleophobic coating

This is the horse's expensive top lens set of the front lens. Enlightenment reduces reflection on the transition from medium to medium (from air to plastic), that is, it stores more information for my retina. Immediately I say - I am not an expert, I can assemble a triplet manually, but all my experience is based not on medicine. But by analogy with the camera just right. Without enlightenment in any way. Then the same desired layer - anti-glare (UPD: this is the same layer, just its second effect, here's a comment from Norno ) . He removes parasitic glare - it seems he copes a little better than my previous points, but I did not notice much of a difference. In fact - and should not have been.

The surprise was the hydrophobic coating. It is noticeable immediately at the time of wiping the glasses (it has become much easier and simpler), plus it runs much better in the rain. On the last day of the flying trees in Moscow, it hit a heavy downpour; I got right into the very core. And nothing. Pants can be squeezed, and glasses are clean. I went down to the subway - I made more condensate, I blew it, it just dispersed to the side of the lens. Fine.

Logically, the oleophobic coating should protect from fingerprints, but there is such a story - if it touched, then it touched, you still need to wash the lens. In the kitchen, I sometimes splash butter in my eyes and on my face while frying a steak, but there are also no significant differences. But the bonus was found: it is very convenient to wipe the glasses with the edge of the shirt, if there is nothing else. One movement - and everything is clear. Previously, you would have to look for a towel or a special napkin.

The problem of hydrophobic and oleophobic coatings is that they lie in the upper layers - and are gradually washed out. Normal coverage lasts 3-5 months, depending on the intensity of wiping the glasses. The most expensive - up to a year or even two, if you're lucky. That is, the service costs 100-300 rubles per month. Not sure what is cool.

Dual UV filter

Cuts off UV light that causes corneal burns. This is important for the mountains and my native Astrakhan. By the way, the cornea allows enough UV to reach the lens, so if you have it artificial, you can change it a bit to start seeing UV on short waves (in theory).

The artist Claude Monet, by the way, underwent just such an operation and began to paint the near ultraviolet after about 1919. Notice how the gamma moved. Here is a brief history of the problem in English, and here you can see his paintings by years.

But for us it’s important that if you finish the cornea burn, then there will be “night blindness”, and then the epithelium will grow again. Not really touching the depths of the eyes. But the proofs are bad, there is an opinion that inside the eye UV can bloat cases. But even old data is enough to understand that the filter is somehow, but needed.

The problem is that the “arms race” has focused on cutting off another half-percentage point — here the difference is in the quality of the coatings, and the cut-off of the flow behind, which is reflected from the back of the lens and comes to the eye. Nikon causes two layers: UV reflection forward and UV absorption on the back side of the lens. This is justified, but given the sharp increase in the price of points, I would say that this is justified only in cases where money is the last thing that bothers you. Because an even greater flow gets into the eyes from the side, and nothing can be done about it (only in the car).

Plastic, even in the base without coating, passes much less UV than glass, by the way.

Blue filter

This is the second moment that unexpectedly struck me. Prior to that, optometrists regularly persuaded me to a miracle coating that protects against the harmful radiation of a computer monitor. Judging by the bulging eyes and the lack of proof, perhaps tachyon. How this garbage is arranged and what exactly it does, few could explain. From one beautiful girl, I even heard that "the coating protects from electromagnetic impulses."

It turned out not so. It turned out that for the last couple of years many have said that it is necessary to block a part of blue light. In particular, from the LEDs (they are something too bright in blue) and from the usual scattered in the atmosphere of the sun. The baseline study here , it was concluded that at a wavelength of 415-455 nanometers, most retinal cells die. In animals. In comparison with other wavelengths and darkness.

The second factor is contrast and fatigue. It is assumed that by observing a warmer range, we are less tired. This is for me a well-known thing after years of choosing the optimal gamut on monitors. The reason - blue and violet light has the shortest wave of the visible. The consequence is that they focus a little on the wrong spot where our green focus center is. And if a person has no hardware problem with the other end of the scale - red, the blue on the resulting picture blurs the focus a little.

Here are a couple of links - carefully, they are compiled by the manufacturer of the lenses, so you should not read the texts themselves, but only lists of references.

As a result, I was put in a blue filter glasses, cutting off the very peak where the eyes are most sucks, 400-450, but transmitting 96% of the light in the range of 469-495 nm. I assumed that it would not be worse, but better, well, I’ll figure out the situation. The circadian rhythm is regulated 470-480 nm (the brain understands that it is necessary to wake up by these rays - there is even a trick to not be broken in the morning, the blue lights are set on the morning in a closed room, and it is much easier to get up).

The result - it may, of course, be wildly useful, but it is completely unsuitable for working at a computer. Firstly, this infection actually changes the gamma in the warm side. And tangible. And it’s not only critical for me to see the exact color, but also, as it turned out, it really infuriates when it’s not like that. True, you can get used to the week.

Secondly, there is a very strange bug either with this coating, or with UV absorption - new unusual parasitic glare from LED-technology and gas-discharge lamps. Look like light stripes on the edge of view, and it really hinders. For the first time I noticed how many LED displays I have in and around the workplace. It is necessary to turn a little sideways - and everything, hello, in the eyes of their weak ghosts dance. For the last 8 years I have been wearing glasses with no visible rim on the bottom and on the side (there is a fishing line everywhere), therefore, I assume that most likely this is not a bug in the end part of the lens.

In general, walking on the street - yes, working in a room where there are normal curtains on the windows - no. Probably it is useful that the eyes do not get tired, the effect of increasing the contrast and more buzz for the eyes is really observed.

In general, you can calibrate the gamma on the desktop, problematic - on the phone and tablet. But there will be no effect.

Also pay attention to the intensity of illumination: in the experiment, it seems, it was used quite high (typical of sunlight). In modern monitors, it is orders of magnitude lower. This means that only some high-energy photons will “pierce” the protective layer of the eye and sweep into the depths. That is, the fear of blue is somewhat exaggerated by marketers.

Progressive lens

This is my hell. Good doctors riveted my lens, which is made on the principle of progressive, but more difficult. The progressive layers go from top to bottom with a linear gradient, and this gradient has a radial gradient. Subjectively. Here I took them through, see:



Here you can see how gamma gets warmer (the green gradient on top is the effect of the LCD monitor, see the color on the same horizontal level as the glasses). And you can see a little chromamber on the right and bottom. In her eyes a lot.

Correctly called "lenses with the support of accommodation." Immediately warned that I will get used to relish - from 2 days to 2 weeks.

On the first day, as in space - if after the first experience of contact lenses I was afraid to fall, then my head simply ached from the surrounding melting. The first five days you can beat the head against the wall, then it becomes more familiar. Almost looked through the center of the lens - the objects are already blurred. I did not know that so often and so actively using peripheral vision with glasses. Two weeks later, the eye together with the brain learned to quickly accommodate. It turns out that if you continue to look at the same object, it will become clear. That is, the muscles of the eyes are constantly moving, and it must be cool.

But no. If your monitor takes a little less than a field of view, this is hell. First, you have to turn your head. Secondly, which is much worse, this lens gives some type of chromatic aberration around the edges, as a result of which the text becomes colored with blots. Blue and red. I saw a similar effect in the Glass-8 stroke when flying across Greenland — there are two polarization layers so that the Greenland pilot is not blinded by glare from glaciers.


^{The river is really green, do not worry, there is a blue above}
In the end, I honestly tormented two weeks after the desktop and changed it to ordinary glass with constant correction and without bluetooth. I was pleased that in the office they have developers with two screens with the same lenses, and they are fine. Return "incompatible with the brain" - about 1%.

Now, about the thickness of the glasses. I now have 1.67 plastic, the glasses are incredibly light and feel much more “airy” than the previous ones (I don’t know from which one they are, but this is no longer glass, but a polymer). The thinner the plastic, the higher the chance of catching chromatic aberration, so I would recommend stopping at 1.6 or thicker if you need a lens more curved than -3 (the rationale for the fig threshold, just according to my survey in a pair of optician for returns). Thin plastic - evil for optics. Although, of course, here is the question of what you like more - problems with distortion or problems with chromatics. Because the thicker the lens, the (on average) the larger your eye becomes like a fisheye lens. UPD: here is an interesting comment about this from iskatel .

Yes, and surveys. The first survey was more than an hour with all the chips, including taking into account the inclination of the head and the correct fit, the second (for conventional lenses) was much faster - they collect data once and even take pictures of the place where, taking into account your usual inclination of the head, the center of the pupil is relative to the lens . Past optics after such a course on riding on different devices, I do not trust exactly, just to find out how it can be. But the pupil was not enlarged (I already went through this very traumatic human dignity procedure earlier to find out that everything is OK inside the eye, and at the same time that there is no spasm either). Another feature of Nikon is that instead of a prescription, they can give a card with a barcode, which opens their partner optics with access to the patient's profile. Along with it, you have to ask for a regular paper recipe - they give it without question, but at first they forgot in the central office: there is not a trading point, but a case study analysis.

With a complete correction, the world around has changed dramatically. There were more beautiful girls in the subway, the products stopped losing on the shelves when we returned from the Astrakhan Biosphere Reserve, I immediately realized that it would be much more difficult to watch birds in old glasses.

All These two and a half features about the full correction, a blue filter and aberrations on a thin plastic are useful to know. Cheap glasses may be better. Consult with your doctor, read the research, require proof after defoaming foam.

Next time we will analyze the worms. Without a hammer.