May 26, 2010
Blog Kindergarten. A Bossy Tutorial: Astigmatism
Here’s the deal: Bossy’s daughter has a congenital eye anomaly, which means her visits to the Ophthalmologist occur with the kind of frequency she knows all about those extraneous Hs and Ls in the word Ophthalmologist, which has nothing to do with this post — welcome to Bossy’s scrambled eggs brain!
Fast forward to yesterday at the eye doctor’s office, when Bossy’s daughter was fitted for contact lenses. Like many of us, where us equals Bossy and the other people who don’t know if it’s fitted for lenses or fit, Bossy’s daughter has an astigmatism.
“What’s an astigmatism?” Bossy’s daughter asked Bossy the eye expert last night. Bossy, by the way, who has shared this diagnosis her whole life, but was never sure if it was astigmatism or a stigmatism.
So Bossy decided to research this condition for her daughter, utilizing only the most reputable medical sources, which means Bossy looked it up on Wikipedia. And here is what she learned:
Astigmatism refers to the image-formation property of an optical system which focuses a single point source in object space into a single point in image space.
Why didn’t you say so — that explains everything! But it gets worse:
Astigmatism is applicable only in the approximation provided by geometric optics. In reality, image formation is at best diffraction limited and point-like images are not possible.
Image, point, object, space, diffraction. Bossy doesn’t know about her very wise council, but after a morning invested in Wikipedia, this is what Bossy got out of it:
So Bossy decided to take a closer look at astigmatism — and see how Bossy did that? Made a visual pun right here in the middle of her eye tutorial?
The first thing Bossy discovered is that astigmatism most often refers to an irregular curvature of the eye’s cornea:
The cornea acts as the transparent window over the part of your eye that has its color, and it is here where most of the focusing power of the eye occurs, as it bends and focuses light onto the retina in the back of the eye:
When the cornea has an irregular curvature, as in the case with an astigmatism, the cornea still bends light, but it focuses the image onto the retina at two different points. It’s this discrepancy between the two refracted planes which result in blurriness:
The amount of blurriness and the ability to correct for it with standard eyeglasses or contact lenses has to do with how many diopters big the astigmatism is:
Is Bossy’s daughter getting contact lenses for the first time? I still remember when I got my first lenses at 12. I felt so grownup and important!
I’m still thinking about who and what for dinner…
Thanks for the excellent tutorial, Bossy! I always knew the irregular cornea surface part, but that is all I could have told you about my weak eyeballs before I read your tutorial!
Thanks for saving me hours of research that I never would have done anyway.
Bossy’s daughter was definitely styling with her patch. No pirate look for her! Good luck with the contacts.
Take care, p.j.
Aww, Bossy’s daughter with her baby teeth and pink patch. She looks darling. But, as a mom, I would cry too.
Thanks for the tutorial. I’ve always wonder what an astigmatism was but was too lazy to luck it up. Now I don’t have to.
Sadly I already KNOW what an astigmatism is. It’s sucky, that’s what it is. I own one too. Thankfully not to the serious glasses and contacts level… just to the bloodshot eyes when tired level.
Hugs to Bossy’s daughter (and to Bossy as I look at the patch pic).
BB
You should know that I nearly died laughing at “John Cusack enters your cornea”.
I nearly died laughing several times through this – dear Gah, Bossy, your brain and its connections both frighten and impress me. Diopter, ’nuff said.
Cheers! I still don’t get it. It’s me, not you. This is the kind of thing that makes me crazy.
I, too, am the proud astigmatic. I think this explains why I am a terrible shot at the shooting range so if ever called upon to blow someone’s brains out, I will opt for the torso instead.
I use my astigmatism as an excuse for my terrible depth perception.
I was confused until you said the eye diagram could double as one for a blocked milk duct, at which point I spit water onto my computer. After i dried it off, I kept reading and the blurry John Cusak actually cleared it all right up for me. Thanks, Bossy, for the tutorial!
I have astigmatism too. Boring!
Does it matter that I barely even skimmed the text, and mostly just looked at the pictures? Because it’s not like I haven’t had “an Astigmatism” for my whole fucking life or anything. Hee!
I have had “astigmatism” forever and even with your help I’m not really sure exactly what it is. I do know that I need to find out about contacts that correct for astigmatism and are bifocal. It’s either that or wear glasses all the time and since I’ve spent 10 years pretending I don’t really wear glasses that would feel like giving up.
As an optician (er, chick who knows about eye stuff), I loved this post!!!
Astigmatism, blocked milk ducts, John Cusak , newly identified dinosaurs, and roasted almonds.
This is why I heart Bossy.
my oldest has astigmatism & needed glasses at 3. she has some pretty cute ones, but can’t wait for the day to be fitted with contacts. she’s only 8, so we’ll probably give her a few more ticks around the sun.
I have this too! Or, I should say, I had this. I finally, at the age of 42, went and had Lasix surgery, which sister mercy is HORRIFYING!! But, I can see!! Distant things, I can see!!
Unfortunately, now I can’t see close up.
Reading at arms length, anyone?
Good for you, little Bossy!! I remeber my first pair of contacts. It took me about a month after wearing them to stop pushing up my “glasses” off my nose!
Dear Bossy. An astigmatic camera is used for Barbara Walters, Pam from Dallas’ skincare ad and numerous shopping channels.
Isn’t the Diopter the cousin of the Triceratops?
I have an astigmatism which means I can’t buy the $20 I-cannot-see-I-am-blind reading glasses at the pharmacy. OH, NO! I have to get the $400 prescription reading glasses.
LOVE your alternate uses for the photos. Now I want roasted almonds.
I had to wear an eye patch as a girl, but mine was not pretty and pink. Now I’m all jealous.
Oy. I have a real problem with matters of the eye. Hearing about those matters of the eyes literally curls my toes. Really. They are curled under as I speak. When I see the eye doc twice a year, and they do special testing mapping the nerves and seeing where my eye is thick or thin, the doc shows me images of my eye. I’ve told him not to do that. I’d prefer he cover all eye related posters in the exam room, but I guess I am not his only patient. Someone out there apparently likes those posters. (toes curling again). Anyhoo, when he shows me all the computer images of my eye, he has someone standing by in the room just in case I keel over, which I have done. I want so badly to put my fingers in my ears and say, “I can’t hear you! La la la la” which is what my kids used to say to me. I know. Grow up!
Very smart to get the contacts while NOT in school. Because that learning curve will put an extra hour into the daughter’s morning routine. *squirtjab/drop/curse/squirt/drop/curse*
Oy.
Also I prefer to have astigmatism if a Diopter is in the vicinity.
My daughter has the nearsighted-farsighted-astigmatism thing. All I know is that she needs 2 different contact lenses that come from 2 different companies and cost an arm and a leg.
She just couldn’t do the contact thing until she was 18. Too skeeved out about sticking things (and fingers) in her eyes.
Chesapeake Woman said it perfectly!!!!!!
So, is this anything like cataracts? “Cause I just had a new lens put in an eye. Piece of cake—-and I can see!!!! (sort of)—-but it happened last week—so it’s early
Wow, thanks for all the definitions. But I still have no idea what that means in relation to those contact lenses that started it all.
I had terrible vision issues and a really really bad astigmatism when I was younger. They didn’t even MAKE contacts back in the olden days for people like me, and when they did they were hard contacts and very itchy and uncomfortable and expensive. Ick
Anyway, science finally caught up with my needs recently and I got a special kind of LASIK done and now I’m all better and it’s almost easy to forget the days when I had a stigmatism. Er, an astigmatism. I learned the right way to say it when I had the surgery done.
Other problem words for me throughout history:
a coma vs acoma
pneumonia vs ammonia
I like the pink eye patch look so much I’m getting one, in orange. No wait — TWO. Twice the fun.
I have been told by several optometrists that I have the steepest curvature they’ve ever seen. I wore soft contact lenses for 20 years, from age 14 (1982) to age 34, when they just suddenly became too painful. Those earliest pairs in the ’80s were probably experimental. Every time I went for a checkup a new prescription was needed, and it always took multiple fittings to get the right pair — either the fit was wrong or the prescription was wrong. (It got worse when I married and H’s career took us new places every couple of years, so I had to find a new optometrist for every checkup.) Some optometrists did not have the patience for me, others enjoyed the challenge.
Do not get discouraged if the first pair of contact lenses is not right. Remember, there should be no discomfort at all if the fit is correct.
“An astigmatism” is the thing that, when I get new progressive-lens glasses with ever-huger astigmatism correction, makes going down stairs treacherous cause my legs look two miles long, my feet look like tiny bound Chinese feet, and the stairs themselves are nigh on invisible.
Why is it that when you wrote “diopter” and showed that particular dinosaur, it made perfect sense to me?
My son was all “What ARE you reading?” Then had the audacity (cousin of astigmatism) to ask “Who is John Cusack?” I swear I brought the wrong boy home from the hospital! Quite possible since I can’t see a damn thing without my glasses – but I don’t have an astigmatism or a dinosaur. Just plenty of John Cusack movies.
Oh, and Bossy’s Daughter with her patch and little, bitty baby teeth = too, too precious for words!
I tell ya, this is the most entertaining blog. Not only is Bossy hilarious, some of the comments left here are equally hilarious.
If you have astigmatism in both eyes, do you have two stigmatisms? I got em too. I remember the things that my kids had to deal with and while at the time I was sad and worried when I look back on them now, I’m heart broken. I digress. That daughter of yours is a doll – when she was a baby and now. A Doll.
Eye am afflicted with astigmatism, too. (Get it? “Eye am”? Jesus, I crack myself up.)
LASIK! I love being able to see!
Bossy, I had to wear an eye patch for years, for lazy eye (NOW I have a stigmatism as well.) It was “flesh”-colored and got sweaty in the summer. The kids called me a pirate. I often just took it off as soon as I got to school.
Thank God my opthalmologist died when I was 11.
Great, thanks. My eyes just let down.
Great post, and I love the diagrams.