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Are my eyes microscopes?
June 5, 2009 8:56 AM   Subscribe

Does my severe myopia give me close vision super powers?

I am severely myopic. I don't have my eyeglass prescription in front of me, but trust me, my eyes are bad. My opthalmalogist says I'm one of the worst he's treated. [I asked another one once to quantify it for me in 20/20 terms. He said he could figure it out with a calculator, "but that reference scale is not for people like you."]

One of the benefits (if you can call it that, and I'd like to) is that I have high visual acuity for close-up detail. I can focus clearly on very small things when they are an inch or so away from my eyeball.

And, while I can't find any scientific evidence to support this theory, my personal experience seems to suggest this ability is quite a bit greater than it is for normal-sighted people. I want to know *how much* greater. Obviously, I can't trade eyes with anyone for a test, but I believe I can see, focus on, and discern very small details that most others cannot.

Am I nuts?
posted by OilPull to Health & Fitness (27 answers total) 8 users marked this as a favorite
 
Probably not. I'm fairly myopic, and my close vision is clear.
posted by kldickson at 8:57 AM on June 5, 2009


I know that one of the trade-offs with my lasik was that I had to sacrifice my close vision. So totally worth it, though.
posted by MrMoonPie at 9:02 AM on June 5, 2009


I have confirmed what MrMoonPie says with my own optometrist. The close-up visual acuity is better than "normal" vision, and would be reduced through lasik.

I frequently take off my glasses to work on small things.
posted by odinsdream at 9:05 AM on June 5, 2009


Obviously, I can't trade eyes with anyone for a test

You can, sort of. Get a video camera and put glasses in front of the lens, then adjust the focus on the camera until objects are clear in the viewfinder. Then move the camera away from the lens and you'll be able to show the world how you see the world.
posted by Brandon Blatcher at 9:07 AM on June 5, 2009 [3 favorites]


This makes sense from an optics perspective - being myopic is akin to having an extension tube installed on your camera. Extension tubes give you the ability to focus on objects closer up, but you lose the ability to focus on things farther away.
posted by 0xFCAF at 9:13 AM on June 5, 2009


Quite right, you get significant magnification of near vision when you are near-sighted. Microscopes no, but my eyes are something like 3.25 diopters of correction and it's about 2X magnification without my glasses.
posted by davidnc at 9:20 AM on June 5, 2009


Never been able to test it, but I am the designated finder-of-tiny-things in my family, and the most nearsighted. Lost pins, dropped screws, hidden easter eggs, shells, fossils, four+-leaf clovers- if it's difficult to see, I'm likely to find it first.
posted by notquitemaryann at 9:29 AM on June 5, 2009


On the redesigned $5 bill, the words "FIVE DOLLARS" are microprinted in the oval shapes on the left and right borders. I can read them.

I think my uncorrected vision is something like 20/2000.
posted by Joe Beese at 9:33 AM on June 5, 2009 [1 favorite]


Obviously.

I can see much more closely without my contacts in that I can with them in.
posted by delmoi at 9:55 AM on June 5, 2009


On the redesigned $5 bill, the words "FIVE DOLLARS" are microprinted in the oval shapes on the left and right borders. I can read them.

I can too, and I'm wearing contacts. Without them, I'm like -5 in one eye, -7 in the other, but I would think that contacts bring that close to normal vision.
posted by nasreddin at 9:58 AM on June 5, 2009


We can use math to quantify this. Imagine the graph for 1/x, label the X axis "focus setting" and the Y axis "subject distance". Your eye has some range of focus settings. For myopic people, the range of focus settings starts somewhere past the Y axis (thus no focusing at infinity) and extends some distance to the right. For hyperopia, the range starts somewhere to the left of the Y axis (negative X values are worthless), but has the same length along the X axis as the myopic people. People with presbyopia have a shorter range than people who don't. Also note that being able to focus at infinity* is not the same as being able to resolve objects arbitrarily far away - this is simply "Can you perceive stars in the night sky as points rather than fuzzy circles?".

Thus to determine the extent of your super powers, you'll need to take a few measurements. We'll assume you can focus at infinity, call that A = infinity. Start with the closest object you can focus on with your glasses on, call that distance B. Then measure the farthest object you can focus on uncorrected, call that C. Measuring the closest object is going to be tricky, this is the one we'll calculate. Solve for D in this equation:
(1 / B) - (1 / A) = (1 / D) - (1 / C).
The difference between B and D is the "bonus super vision" range you get from taking your glasses off.

* This analysis disregards hyperfocal distance, but the error introduced from that should be minimal.
posted by 0xFCAF at 10:05 AM on June 5, 2009 [1 favorite]


It's common for myopia sufferers to see better up close with their corrective lenses removed. The lenses don't allow for the fine mirco-focus adjustments that the eyes need to make. I'm fairly certain that in general, a finer attention to closeup detail would have much more to do with neurological processing rather than physical eye issues. There would need to be a study with a pretty large sample of 20/20 vision possessors versus myopic vision for any real trend to be honestly discussed.
posted by Burhanistan at 10:09 AM on June 5, 2009


Look at it this way: the visual cells of your retina are like pixels, and are pretty much the same size from person to person.

Near-sighted people can hold an object closer to their faces and focus on it clearly, therefore it occupies more of their visual fields than for normals, which means your retinas are devoting more cells to it, so there are more pixels, greater dpi, and, inescapably, higher resolution.

I'm a high myope (-10-12 in each eye) and I've always been able to see things other people couldn't.

I can easily read the Compact OEDs without magnifiers, and when I was a kid, one of my Christian friends had this little novelty where the Lord's Prayer was on a piece of type 1/8" X 1/8", and I could read it off effortlessly.

But there was plenty of stuff other people could see that was completely lost on me. Whenever I got a new pair of glasses (every six months), I'd have two weeks of seeing all kinds of ravishing texture, but every day during that time less than the day before, as my myopia lived up to its 'progressive' moniker, then a regime of more gradual decline until my next exam. I used to pitch in little league, and I always had to pretend I could only throw fastballs even though I had excellent breaking stuff, because I couldn't let the coach find out that I had absolutely no chance of seeing how many fingers the catcher was holding out. I couldn't see the ball leaving the pitcher's hand when I was batting, either, or tell whether the ball was headed in my direction when I was playing the outfield, until it was out of the infield.
posted by jamjam at 10:44 AM on June 5, 2009 [1 favorite]


Here's another agreeing anecdote... I've always been myopic and even when I was in school, around others who presumably were at the optimum point in their lives for the quality of their natural vision, people were amazed that I could print things out in four-point font on the laser printers of the day and be able to read them without a magnifying glass. (And believe it or not I wasn't printing out cheat sheets but long encyclopedia articles on single pages to save paper.)
posted by XMLicious at 11:11 AM on June 5, 2009


I hadn't realized this was part of myopia. I put my notes up on reducing massive documents to a few pages up on my site. Now I get why all my friends couldn't pull better than a font size of 6 without a headache... none had glasses! It's 3 for me, and 2 is visible but hurts.
posted by jwells at 11:33 AM on June 5, 2009


Thanks everyone for the answers.

I marked a couple 'best,' mainly for the creativity or work put in, but I really don't know (as yet) which are truly best.
posted by OilPull at 11:47 AM on June 5, 2009


I'm fifty. I'm myopic.

I pull my glasses off to read.
posted by St. Alia of the Bunnies at 12:24 PM on June 5, 2009


Now that this is more or less answered, can I just say how cool this is? I have terrible myopia too, and have noticed this phenomenon but I always thought that was just me experiencing normal vision. I didn't realize it was actually better than normal. Cool!
posted by MadamM at 1:03 PM on June 5, 2009


I'm super-myopic. I think of it as having a built-in magnifying glass. When something needs extremely close examination, I'm the one who can do it. Others can't see the detail.
posted by PatoPata at 2:51 PM on June 5, 2009


You might find this article published in 1981 -- Close work without magnifying lenses: A Hypothetical Explanation for the Ability of Ancient Craftsmen to Effect Minute Detail -- to be of interest.
posted by peacheater at 4:42 PM on June 5, 2009 [1 favorite]


This thread is wonderful. I've been very nearsighted my entire life; I always assumed that, once they got close enough to see, how I saw things was how normal people saw *everything*, and have always been a bit frustrated by that. Now it turns out that there actually *is* an upside to the whole thing, and it isn't just losing the genetic lottery. How great!

This also helps explain why I am so much more fastidious about tiny specs on the dishes than my wife, and why I always feel like I got a rough shave.
posted by paisley henosis at 4:57 PM on June 5, 2009


If you want to show the world how you see it, have them put on reading glasses that are the opposite of your glasses prescription. I wear contacts (-6.5) and have a pair of +3.5 reading glasses that I use when I need my superhuman microscopic natural vision back.
posted by gjc at 6:32 PM on June 5, 2009


Hm, I'm severely near-sighted as well and basically I have to hold things so close to read that I basically can only focus with one eye.

How are you all -10 or -12 and still manage to focus on something? I think I'd end up cross-eyed trying to read without my glasses on.
posted by polexa at 10:08 PM on June 5, 2009


Polexa, I take my glasses off for the instant magnifying glass effect. I'm -9.5, and the point at which things are in focus is a little less than an inch from the tip of my nose. I use just one eye to examine whatever it is. There's no way I could read a book that way, but I'm 48. When I was a kid I could apparently read by literally burying my face in a book, at least according to an old photo I have. I might have been less myopic then or have simply "turned off" one eye.
posted by PatoPata at 7:15 AM on June 6, 2009


Peacheater, that's a fascinating article. Thanks for posting it.
posted by PatoPata at 7:20 AM on June 6, 2009


If you will...
My eyes kept me out of the Army when drafted in 1970. One is -8.0 and the other is -8.5. (The limit was +/- 8.0.)
My mother-in-law was an avid stamp collector and would ask me to describe details to her. I would remove my glasses and tell her things about the stamps that were difficult to see even with magnifying lenses.
Now, at 57, this "superpower" is diminishing.
posted by Drasher at 9:18 AM on June 6, 2009


Wow. me too.
posted by grubi at 12:49 PM on October 19, 2009


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