I know from past experience that when given binoculars I can stick my eyeglasses in my pocket and attain an excellent sharp focus with the binoculars alone, this deapite formidable nearsightedness and decently impressive astigmatism.
Now my eyeballs have decided they are old & tired and they will no longer do the focusing-at-short-distance-range thingie.
I don’t want bifocals or those gradual-transitional lens variants. What I really want is a pair of lenses and a focus knob. Anyone make such a contraption without it being awkwardly cumbersome?
I’ve seen variable-focus lenses that were made from a pair of transparent membranes into which water was injected or removed to change the curvature. I think they’ve been used in eyeglasses for use in developing countries.
I’m not clear (hah!) on whether this is specifically for long-range viewing (binoculars replacement) or everyday use, but assuming the latter, consider my story:
I have nearsightedness in the range of 20/400. Once I crossed the magic “40” threshold, my sharp near vision - traditionally where I shine - has gotten closer and closer, so that now, without aid, I can only see clearly out to about 10 inches, which is pretty useless except for threading needles.
Because I work with computers all day, I found I was wearing reading glasses most of the time (along with my contact lenses for distance vision), which effectively gave me the worst of both worlds.
Then about 3 months ago I gave “bifocal contacts” a try. My optometrist said they only work for about half the people, but let me say that, 30 seconds after I had put them in, I was the most thrilled I’d been in years (more of a commentary on my boring life, I suppose). I really felt I was back to having 20-year-old eyes. I could see distance about 20/20, mid-vision (say, 30 feet) about 20/30, and read tiny type on everything. And it was all seamless and instant! For me, it truly is a miracle.
Again, apologies if this is not the problem you are trying to solve.
I’m in a situation similar to Raza’s but I have no vision in my left eye. Because of this, and because I am keenly aware that most people who lose an eye do it while performing activities they thought were safe, I feel much more comfortable with a polycarbonate lens in front of the good eye. I have vision in the good eye around that 20/400 range, a -7.00 diopters. I had them correct with a contact lens to give me good reading and close vision, it’s around a -6.0, then when I need distance vision I use glasses for that. I’m around 20/40 without my distance glasses.
Basically if I’m at my computer or sitting reading I go without glasses, but for pretty much all other activities I use a small additional correction for distance, and it gives me the advantage of the shatter resistant lens.
The next best thing is to ask your eye doctor to prescribe a combination of contacts AND eyeglasses. If your eyes have grown so weak, they actually CAN prescribe such a combination. usually, the contacts will be at their highest strength so the eyeglass lenses can be as thin as possible. Sounds odd, perhaps, but it IS done.
Beyond this, such a device is not on the market because of aesthetics. I mean, even coke bottle glasses weren’t all that flattering. And, what you’re asking for is to wear twin telescopic lenses on your face!
Since at least a couple of you don’t appear to be too concerned about appearances, I thought I’d toss this out as a possible alternative:
I recall seeing a movie once in which Kirk Douglas played a very lively but quite old man and he kept two pair of glasses hanging from cords around his neck, one for near and one for distance vision (his middle vision was apparently okay). Each cord was a different length and his distance glasses hung the lowest, hence it was easy to know which ones he wanted to put on in order to see what he wanted to see.
This seems to me to be an excellent if somewhat inelegant way to have near, middle and distance vision readily available (even if requires a third set for the middle range) for someone who either doesn’t want to or can’t go the contacts route and isn’t too concerned about how it would look.
1.) A European company named Varioptic now makes compact liquid lenses that put the old-model liquid lenses to shame. They’re compact, and require a small battery to focus, which is done by applying a voltage to the interface bewteeen two immiscible liquids. The unit is completelt sealed, and doesn’t leak. Unfortunately, the lens aperture is only about 5 mm, so you’ve got a pretty small window. They’re planning on using these in cellphone cameras and the like. But maybe in a few years:
2.) Old-style liquid lenses use liquid sealed in a slightly stretchy membrane, and can be adjusted by twisting the case. One innovvative design uses crossed cylindrical lenses. A bit cumbersome. Bigger than the Varioptic lenses, but still not big enough. And they tend to leak.
3.) Polaroid engineers develo0ped an intriguing system, consisting of two complex-shaped plastic pieces that had quintic surfaces. When placed against each other, they produced a single lens with a single power across the aperture. They developed types that could be slid linearly across each other, and another type that could be mounted on a common spindle and rotated. It required a computer-controlled diamond-turning apparatus to make the mold, and careful plastic injection-,molding to get it to come out right. Alas, Polaroid is no more. The division that made these was spun off as an independent company that has since been bought by an Asian conglomerate. The last I heard, they weren’t making these anymore. They only used them in cameras.
4.) You can mount two lenses in a frame and vary the power by moving them relative to each other. But iyt looks klunky and kludgy, and you wouldn’t want to wear it.
5.) Zoom lenses are even klunkier, consisting of three or more elements. You wouldn’t want to wear them.
I was in the optometrist the other day getting new glasses for my wife, and on one of the top shelves they had a weird contraption. I asked what it was, and it was essentially what (I think) you are after.
It was like a pair of glasses, in that it sat like a pair of glasses over your face, and had a set of lenses in it. Then out the front it had another set of lenses, so it worked like binocluars. Each eye was adjustable separately. I did not ask how much they were, however.
They were not very attractive, but not as clunky looking as a pair of binoculars.