Astigmatism Explained

Astigmatism Explained


So, if you’re watching this video, there’s a good chance that you have heard the term ‘astigmatism’ and perhaps you’ve heard that every single time you go in for your eye exam. Well, in this video, we’re covering exactly what astigmatism is how astigmatism affects our vision and our prescriptions. So, let’s take a look. Hey, guys! This is Doctor Joe Allen from DoctorEyeHealth bringing you the very best in tips and education about your eyes and your vision and here on this channel you’ll find a lot of different product reviews as well as educational videos just like this one so if you’re new here, considering subscribing and at any point in the video make sure to check out the show notes and links below for further information about anything we forget to mention. Otherwise, let’s go over astigmatism. So astigmatism is arguably one of the most common things I have been talking about with my patients every single day. It’s a very common diagnosis and it is something most of us, probably have to some degree. The most simple way to explain astigmatism is basically that the structures within the eye are not perfectly round; they’re a little bit warped and because of that, it causes light to bend or refract a little bit uneven inside of the eye and that causes your vision to be blurry, and distorted. However, the good news is that astigmatism isn’t actually a disease, it’s just a condition, and we can correct for that with glasses, contact lenses, and even eye surgeries, like LASIK. Now, to better explain what astigmatism is, I want to show you the cornea. The cornea is the front window surface to the eye. It protects the inside of the eye from the outside environment, and acts as a lens to bend light toward the inner eye. In an ideal world it is a smooth and evenly curved surface to that light passes through it in a uniform fashion. However, most of us have some unevenness on the surface of our cornea, and that uneven curvature is what is called corneal astigmatism. The uneven curve of the cornea can be determined by finding the difference between the flattest and the steepest curve of the corneal surface. Most corneas have some curvature somewhere between 39 and 49 diopters and that number tells us the amount of curvature or power that the cornea has to bend light. If there isn’t astigmatism, as in this example, we’ll say maybe the curvature is 43 diopter in one place and maybe 41 diopter in another. The amount of astigmatism in this example being the difference being between 43 and 41 is two so the answer is 2 diopters of corneal astigmatism. Now, your eye doctor can actually measure this curvature to the eye using a couple of different instruments. Classically, we would use one called a Keratometer which only measure about the first three millimeters centrally of the cornea. But nowadays, we actually use new technology called a topographer, and the topographer will not only just measure the central three millimeters, but they’ll measure but they’ll measure the entire front surface of the cornea making it a little bit easier to identify disease as well as to treat and manage those conditions, such as with specialty contact lenses or even with corrective eye surgery. Now, when light passes through a cornea with astigmatism, that causes the light to be focused irregularly inside and that causes our vision to not just be really foggy and blurry, but can cause your vision to be distorted. Almost in an extreme example, it would look like a fun house mirror, where everything can kind of be wonky and warped. Now most of us are actually born with some level of corneal astigmatism, and it may change in the first couple of months and then it tends to stabilize out for the rest of your life. Now there is another type of astigmatism, and we call that lenticular astigmatism. And that has to do with the shape of the lens inside the eye. And that astigmatism does tend to change throughout our lifetime. First in our adolescent years, as we’re under more visual stress, and then again in our later years as the lens begins to stiffen. Now, when the doctor measures and corrects for your astigmatism, they actually correct for the combination of the two: both the cornea and the lenticular astigmatism. Usually, your doctor won’t measure the lenticular astigmatism by itself because it requires very expensive and high-tech equipment and it really just doesn’t give us that any much useful information. Now, if you don’t know if you have astigmatism or not, we can actually figure that out by looking at your most recent glasses prescription. So, let me guide you through how to read those numbers. So, if we look at a prescription pad here and zoom in here we are going to see, of course, the first and last name, a date of birth, and then down below we are going to have the expiration date and your doctor’s signature. Now, looking here on the left side you will see two rows, one is labeled OD which stands for the right eye and one is labeled OS, which stands for the left eye. On the top, we have several columns which we can actually work through individually, the first column here is labeled as SPH, which stands for sphere, which is the easiest type of lens that can be made. Under that you’ll see some numbers, the higher the number the stronger the prescription. The number will also have a positive or a negative symbol in front of it, which tells us if the lens is correcting for far-sightedness, or hyperopia, when it’s a positive symbol and near-sightedness, or myopia, when it’s a negative symbol. These next two columns here are going to tell you if you have astigmatism. That first column is the cylinder, and the higher the cylinder number, the stronger your astigmatism correction will be. Again, in front of this number you may see a positive or a negative symbol. However, it is more common to have a negative symbol here because when an optician makes glasses, it has to be in the negative format. If your prescription does have a positive symbol here, well, then your optician has to do extra work to convert it and it increases the likelihood of errors when glasses are made. The next part is called the axis, and the axis number indicates the position of the overall astigmatism through the visual field. And this number will be between 0 and 180. To illustrate this better, we can divide the eye into a pie with twelve equal sections. The astigmatism lies along one of the divisions of this circle. In this case, the astigmatism is along the 120-degree line in the right eye, and 20-degree line in the left. The axes are darkened on the illustration to indicate this. It is actually more common for the prescription when we are young to have an axis closer to the 180 line, and then gradually becomes closer to 90 as we age. So, if you have these number, that’s going to tell you that you have astigmatism. However, the last two sections here describe what is called the add or the additional lens needed to help someone see up close as in the use for bifocals, and the there’s the prism which isn’t used very often, but is necessary for those individuals who have fusion difficulties and may end up seeing double. Now, the good news is that we can correct for astigmatism with glasses, contact lenses, and again forms of corrective surgery like LASIK. The most simple way to correct for astigmatism is with glasses. However, glasses aren’t always the best way to correct for it because we can get some optical distortions because they’re looking through a piece of glass or plastic. And you can kind of experience that distortion by holding up your lenses and looking at a distant object that’s straight up and down. And then rotating the lenses so you can see how the world starts to warp left and right or side to side. And that’s why some people will say that it feels like they’re almost having tunnel vision while looking through glasses as compared to some options, like contact lenses. Contact lenses are fantastic because it actually forms to the surface of the eye, giving you a wider field of view, and can correct for that astigmatism, all at the same time. Now, most contact lenses for astigmatism may actually be called toric lenses and these lenses have a little dash mark that’s etched into the lens and you can hold up the lens to the light and sometimes you can see that little marking. That mark is there so that the doctor can read where the lens is sitting on the eye, and then make adjustments so that you can get the best prescription and comfort in those lenses. Many types of corrective eye surgery can actually correct for astigmatism as well ,such as LASIK. LASIK can actually actually correct up to almost 5 or 6 diopters of astigmatism. So, make sure you ask your doctor if you are a good candidate for those procedures. Now, let me show you what somebody sees when they’re not wearing correction for their astigmatism. I’ll give you the best frame of reference we have a vision chart in the clinic here on the left side and we have some distant objects outside here on the right. We’ll start off to showing what 1 diopter of corneal astigmatism set at about and axis 90 degrees looks like and then we can rotate it so the axis is closer to 180 degrees. We can also do the same thing with 2 diopters of corneal astigmatism, and then we can go over to 3 diopters and then over to 6 diopters. And here at 6 diopters, you can see how warped or bent someone’s vision would be if they were walking around without correction for their astigmatism. Now, again the good news is that astigmatism isn’t really a disease, it’s just a condition that we correct for. However, there are some extreme cases where people will have really high levels of astigmatism and that can actually be classified into diseases. One of those diseases is called Keratoconus, where the surface of the eye, the cornea, actually starts to bulge out into a shape of a cone. Other cases such as Pellucid Marginal Degeneration describes where the cornea begins to thin inferiorly, causing again high levels of astigmatism. Now some people may have had trauma to the eye or scarring that actually caused astigmatism and that again can be corrected with special contact lenses and maybe even just glasses by themselves. Alright, guys, thanks for checking out our video about astigmatism and how it affects your eyes and your vision. If you like what you saw, make sure to hit that like, subscribe and go ahead and share this video with friends and family who may be interested more in what astigmatism actually is. Otherwise, again, this is Dr. Joe Allen from DoctorEyeHealth, bringing you the very best in tips and education about your eyes and your vision. Keep and eye on it! We’ll talk to you soon. *beep* *woo sounds* putting on my cool glasses. Putting on my cool glasses. Ooh, it felt good!

100 comments on “Astigmatism Explained

  1. why does gacha exist? Post author

    We’re blind 😎

    I want to fix my eyesight without surgery because I’m scared of wearing glasses too much

    Reply
  2. jennie draws Post author

    I work at an ophthalmologist office and the majority of our patients have a positive cylinder. So I was very surprised to hear that the negative is more common than the positive. You learn something new everyday.

    Reply
  3. Monica R K Post author

    Wearing glasses since the age of 7, blessed with myopia and astigmatism, is a hell far or close only progressive lenses were a blessing.

    Reply
  4. I D O N T W A N N A D O T H I S A N Y M O R E Post author

    I have this and both eyes ! My eyesight is terrible and I don’t wear glasses

    Reply
  5. Stephanie H Post author

    Wonderful video, just got an eye exam. Turns out I have astigmatism!

    I ordered contacts and noticed they are shaped/sized a little bigger than other peoples contacts. .
    Is that usual with astigmatism contacts?

    Reply
  6. Sc Rf Post author

    I came here because I always would look at lights and have a streak of that light color and I always thought it was normal but I asked some friends and my mom and they did not have it so I got scared but this video made me more calm thank you

    Reply
  7. HRTsAFyre Post author

    I had Radial Keritonomy in the 90's for myopia. One eye was less corrected for reading focus when I hit my 40's and the other one was corrected to 20/25 for distance. I enjoyed clear vision for several years uncorrected. Then it began. At first I needed reading glasses. There was talk of astigmatism. It kept getting worse. Then my vision at a distance started to get blurry. I was reading with my prescribed glasses and a magnifying glass as my eyes grew tired. I simetimes saw double up close and I became disenchanted with eye doctors. Then I got several glasses online after an eye exam. The UV coated "computer" lenses I noticed provided me with clear vision both near and far for most of the day, even though these were reading glasses only. The 2nd pair were progressive vision bi focals for near and far correction, but I could never get used to them or the wavy effect. The UV readers worked for all my needs, until I needed a stronger script.
    Over time, I had noticed my vision had fluctuations throughout the day better in morning the end of the day, my eyes hurt and everything was blurrier. The time the fluctuations start it pretty much immediate now. I still cannot focus near or far. Without glasses and I found the dollar store glasses were helpful for both reading and distance. So disillusioned with eye doctors I just kept getting stronger ones over the last 3-4 years.

    I am wondering if I should see an ophthalmologist for a proper diagnosis instead of an eye exam. My insurance company is sending me to Walmaet or America's Best. I'm thinking they are not trained to deal with my possible RK induced issue. Do I have Presbyopia and astigmatism or is there a refractive error and my Cornea lenses have gotten worse? I want to get contacts for close up, because I cannot see to put on makeup any longer. Then I saw toric lenses on their site. Would there be ok for me or is a hard contact lense or Schlera lense a better option. I am scared of going blind, but don't feel opticians are doing me justice. I am afraid that cataract surgery or lense replacement is going to be needed soon.

    Should I demand to see an eye specialist for a fitting or are these places ok to give me the initial exam and referral?

    Reply
  8. joystick396 Post author

    My astigmatism is so bad that I remember I drove without glasses or contacts one time and my drunken friend had to tell me where things were 😂😂

    Reply
  9. Imel Marte Post author

    my vision worsen due to long study session for college, now the prescription i need to correct my astigmatism makes my vision blurry, so i got glasses (prescribed by my doctor) that cant fully correct my condition but i can still see. Does that mean i'll need a new prescription in the future?

    Reply
  10. Katie F Post author

    I have controllable lazy eyes (meaning I can control having double vision) and I literally don’t know anyone else that can do that so it scares me lol I’ve been able to do it my whole life…then lately I’ve been getting floaters and was told by my opt. That I have vitreous detachment lol what does this mean???

    Reply
  11. KaOsXvP Post author

    I should be studying for my bio/chem quiz in like 2 hours but instead I’m learning about astigmatism

    Reply
  12. Martha Arciniega Post author

    I already got glasses cause astigmatism I know everything about it idk why I’m watching this:P

    Reply
  13. Steve McQ Post author

    Just had PRK on 18/Sep/2019 and still healing, looking better one eye the other still a little blurry.
    Can't wait for cybernetic eyes. 🙂

    Reply
  14. SVR272 Post author

    I wish I could see this mans face, as clearly as you guys can. All I can do is read all the glowing compliments he is getting.

    Reply
  15. GGMudkipz Post author

    Don't know if you are still gonna read those comments here. You told us about prism glasses against double vision. Why is that not a treament option for early stages of mild Keratoconus. ?

    Reply
  16. Gus malunda Post author

    Thanks for information…does eye exercises has any affect on astigmatism or is just a myth….thanks

    Reply
  17. ed denz Post author

    Your diagram of what should be a toric cornea looks more like pellucid degeneration with variable curvature in the same meridian. It’s so simple to explain astigmatism correctly

    Reply
  18. Melissa Johnson Post author

    Mines so bad! Have wasted so much money trying to find contacts I could wear and actually dee out of…no luck. And actually went for a lasix consult and was told it probably wouldn't fully correct my vision but may get it to where I could wear contacts….

    But seriously who would spend $1500+ per eye just to wear contacts 🤦🏻‍♀️🤦🏻‍♀️ not me 😭

    Reply
  19. JLBee Post author

    That's what the D means on my contacts package! Before I got glasses, I had no idea that a straight line existed, and my first day back at school, I was looking at a math worksheet, and just admiring how beautiful the printer made the lines look! I always thought the printer was just bad and would make smudges or uneven lines, but it was my eyes. I can definitely see what I have now, and that also explains why contacts have to be weighted. It takes me about 10 minutes to get used to them and get them right side up, but hopefully that improves with practice. I always use glasses for computer use because I have a coating on them that helps a lot, and one eye is too weak to get a contact, but I like the options.

    Reply
  20. Red Poppy Post author

    I now have 2 pairs: distance and reading glasses. Should I only wear them when I need them or always? Also, if I have R -8/L-7.25 is it too late to reduce the nearsightedness?

    Reply
  21. Robert Sparkman Post author

    I hope you’re a Christian particularly of the Reformed variety, I’ve read that you are involved in medical missions to help vision problems in poorer countries. At any rate may God bless you. Great videos.

    Reply
  22. Afshan Maqbool Post author

    My glasses number for both of the eyes is -1.5, cylender and axis boxes are empty then what is the reason of my nearsightedness plz answer

    Reply
  23. Behonest Post author

    Thank you for this video. My 2 year old, almost 3, has glasses. She’s been wearing them for a year now. She was diagnosed with astigmatism last year and I never really understood what she saw. I knew she would tilt her head to the sides or to the back or forward. I also knew she kept bumping into things. This makes so much sense!

    Reply
  24. jengonz86 Post author

    I have it but when fitted with the toric lenses I could somehow see the dashes in them or it would be fogged looking on my peripheral so they translated mine to regular lenses. I never asked why that was or why it caused it but the regular lenses are better but not as sharp as the astigmatism ones.

    Reply
  25. Luna Redelvour Post author

    Man I would gladly reference my eye prescription or whatever and follow along with this… bUT I ACTIVELY CANNOT READ MY DOCTOR'S HANDWRITING

    You'd think that people in the medical field require good handwriting because y'know people needa be able to read prescriptions, whether it's checking their most recent eye prescriptions or knowing if we need 3, 5, or 8 pills for the thing to work

    (I mean idk in what world you need 8 pills of one medication but I'd argue 3 and 5 are reasonable xD)

    (Note: Medical specialists of the world, I'm grateful, don't get me wrong. Please just note that your handwriting matters and that I'm not mad at all of y'all xD)

    Reply
  26. Lolly Gaga Post author

    I have 5,0 of astigmatism in the right eye and 3,75 in the left eye.
    I also have 2,0 of myopia in both eyes.
    It's hard to find contact lenses for me😭

    Reply
  27. DiabeticlySweet Post author

    My left eye has blurry vision and my right not too bad. Turns out all these years not everyone sees out their one "good" eye better than the other. I was diagnosed about 2yrs ago and when I first got my glasses my brain freaked out like "what is this, what is going on. Took my eyes and brain about a week or so to adjust to the glasses.

    Reply
  28. Ashley Arruda Post author

    Uh is it normal to have your new prescription lenses make you have a headache and like feel like they don’t work at all?

    Reply
  29. Mike Pijoan Post author

    My doctor told me that my astigmatism could not be corrected by glasses. Is that wrong info? After seeing your video I think I might need a better doctor…

    Reply
  30. Noahhh Post author

    I have astigmatism in ma left eye
    There is this place that can do laser eye surgery to fix it and I’m excited.

    Reply
  31. Jason Merth Post author

    Unfortunately this didn’t go into mixed astigmatisms and compound hyperopic/myopic astigmatisms. It would have been better to even go into detail on irregular astigmatisms

    Reply
  32. A lil bit Ritardando Post author

    What's the difference between positive and negative astigmatisms? I have a positive in one eye, but a negative in the other, and I've never really known what the difference between them is.

    Reply
  33. Upon A Day Dreamer Post author

    I'd like to know what happens if you have astigmatism and wear colored lenses. Does it make a difference?

    Reply
  34. Nexus Cabañelez Post author

    Is it called astigmatism where the lights are like stars shining but that's it?. Like if it's in daylight. The objects are just a little bit blurred and smaller? My glasses level is 200

    Reply
  35. Gleancarl Acosta Post author

    Just went to the doctor…
    And my result is
    O. D – 0.50 SPH-0.25 CYL AXIS 180
    O.S 0-25 APH – 0.25 CYLAXIS 150
    REMARKS=SV_MC
    PD=66/63

    I DONT KNOW WHATS THE MEANING.. WEW

    HUHUHUHU.
    CAN HELP ME EXPLAIN THIS DOC. THANKS

    Reply
  36. Nataly Arciniegas Palacio Post author

    Do you have experience with chromatic aberration when wearing glasses?? I've experienced this my entire life.

    Reply
  37. Sit n Spin Post author

    Here's a giggle for you! I have astigmatisms in both of my eyes that affect my diagonal vision, so the left side of life is higher than the right. My home city, in North East UK, is at least 2,000 years old and the part I live in sort of 'dips' to the right. I never knew anything at all was wrong with my vision until I put a picture up on a wall and arguments commenced. What was straight to me wasn't straight at all! In my determination to prove I was right and everyone else was crazy, I went for an eye test.

    I was the crazy one! Anyhow, I'd adjusted so well through my city's natural dip, that glasses made everything wonky! Pushing my wheelchair through doorways turned me into a free remodelling service while I misjudged distances to the extreme. I gave up my glasses and people were again safe to leave their homes without fear LOL

    Reply
  38. Slew 282 Post author

    I see little bright spots moving in my vision when I look at anything bright like a blue sky or snow I have had it checked 3 times and I get no answers any ideas on what I should do next

    Reply
  39. Brooks Kelley Post author

    I found your video on Cataracts and went onto to watch this video next. They are very good.

    I have a family history of the early onset of cataracts. My mother had cataract surgery at 52, my sister at 48, and, no surprise, I started getting them at 55.

    You mentioned LASIK correction. But, I had my astigmatism treated also during my cataract surgery. I have never seen better. Not with glasses nor with contacts. It is the best decision I ever made to select the laser cataract surgery versus the manual lens removal and replacement. My vision is so good that my eye doctor said that he could write me a prescription, but with no need for any correction — except for reading — he threw up his hands and said why bother.

    Anyway, my eye doctor mentioned one thing that I would pass along. There is an additional advantage to getting the laser version of cataract surgery. With no astigmatism to speak of and a good lens placement, future surgery that might be needed for age related macular degeneration is much easier to perform.

    Thank you for the informative video. It was very well done.

    Reply
  40. nirispa12 Post author

    I explain to others that my astigmatism causes my eyes to refract light differently. At night, lights look like they have halos. As I’ve gotten older it is harder for me to drive at night. Another distinct explanation is that a quarter moon looks like a Lima bean without my glasses. Btw my doc says I cannot use contacts bc my astigmatism is so bad!

    Reply
  41. Robert McMahill Post author

    Hi there you should do a video on ocular albinism I have it and it is difficult to explain to friends who want to know more but it’s difficult to explain to them

    Reply
  42. R.A. Monigold Post author

    I am so thankful you decided to become a Doctor. Your personality is so inviting and your "bedside manner" is one of coffee with an old acquaintance. You instill confidence – I find you safe and relaxing. If I lived near you and wanted my vision repaired – YOU would be my only choice.
    Thank you for sharing…

    Reply
  43. RemyRAD Post author

    This was extremely helpful. Thank you.

    I have had my vision problems, since my adolescent years. Noticed at 15 years of age. Partially detached retinas. I personally hadn't noticed any differences. I was accused of looking into the sun. Nope. I knew better.

    I never realized just how incredible my eyesight actually was. I wasn't just 2020. I had, Superman vision. But then I did start to lose my eyesight. I started losing centralized acuity and brightness overall. I was diagnosed with, multiple sclerosis. And my Outlook was dim. I was now virtually blind.

    One morning I awoke. Things were not right. I thought I had a stroke in my sleep. They got me to the emergency ward. MRI revealed, not a stroke. A bad case of hydrocephalus. I wasn't supposed to be talking or feeding myself, or nothing. Generally nothing. And required emergency brain surgery.

    When I awoke, in the dimly lit, recovery room. It was as bright as the sun at the beach. Oh my God. My vision has returned.

    After my brain surgery. When I was able to look into the mirror. I was horrified. I had these little pig eyes. What happened to my eyes? I was told my eyeballs settled back into their sockets. Since the pressure was relieved from my hydrocephalus. And I asked, so I don't have multiple sclerosis? They said they still believed I have multiple sclerosis. But now in remission. But the brain surgery doesn't fix that. I'm the luckiest person in the world.

    My last vision test at, 64 years of age, indicated I was, 20/30. But on the big LCD displays. At home. At the bar. I'm still able to read the small type. From across the room. My friends can't. And I complain about my vision not being as good as it once was. Now I know why the ophthalmologist, looked at me cross eyed. When I said, I was having trouble focusing, on the street name sign. From one block away. He told me to get out.

    RemyRAD

    Reply
  44. PaintmanJohn Post author

    His shirt is PART OF THE EYE TEST !!!

    Seriously. This is the most descriptive and easily understood explanation I have ever seen.

    Reply
  45. Fred Seeking Bible Truth Post author

    Oh sure you wear a shirt a person with Astigmatism can not even look at to explain astigmatism. 😉 EDIT : I have a question for you. Why is that kind of shirt hard to look at when you have Astigmatism? Also why is it hard to look at red or top of blue or blue on top of red. Like the image on the upper right of this page https://en.wikipedia.org/wiki/Chromostereopsis ? I can not look at that with out my eyes hurting. It looks like the blue is hovering above the red or the red it hovering above the blue. Kind of 3d but hard to look at . This is the way astigmatism works for my of my family as it runs in the family. Looking at patterns is the worst though. Like I said your shirt is very hard to look at and hurts my eyes. SO my question is why as I do not think the video answered that and just confused me. Not your fault at all I can get confused easy. I am always searching for answers to questions, although mainly biblical question as the name suggests. Anyway, thanks for the video.

    Reply
  46. The Next Chapter Post author

    So, what "bends" the cornea? I've heard that it is the tiny muscles that move the eyeballs. Over time, they squeeze on the eyeball resulting in a more ovoid, less round shape. Have you heard of the Bates method? Taking your eyes to the gym to work on those muscles can theoretically restore the shape. The Bates method is a series of exercises to perform that seem to fix quite a few problems with vision, especially astigmatism. There are quite a few anecdotal testimonies here online where it has worked.

    Reply
  47. lee shafer Post author

    My astigmatism results in giving me amazing low light or nighttime vision But my DR said i wouldn't benefit from glasses BECAUSE OF MY ASTIGMATISM! WAIT-3:17 DID YOU SAY LASIX CAN BE USED TO CURE THIS? WTF SHE TOLD ME COULDN'T BENEFIT FROM ANY OPERATION-THIS WAS ONE YEAR AGO.

    Reply
  48. Nikita WhoopAss Post author

    I'm new to wearing contacts. I have astigmatism in my left eye. I can feel the lens in my eye and it bothers me. My right eye I can't even tell I have a contact lens in it. Will you always feel the lens in the eye with the astigmatism? Should I go back to my eye doctor? I dont want to feel it all day long in my eye.

    Reply
  49. realvanman1 Post author

    So, all this time, I have been of the understanding that my eyeballs are egg shaped instead of spherical, and that condition was known as an astigmatism… Now I don’t know what to think!

    Reply
  50. Maureen Gannaway Post author

    Thank you Doc. Now I understand what my type of sight is and my prescription that my Dr gave me for bi-focals. I don't like them because I feel off balance when I look thru each part. Can u tell me what my options are. I'm 54 an just got bi-focals. Thank You

    Reply
  51. mleii1169 Post author

    Hopefully you read questions from your older videos. I have some questions about astigmatism.

    If it's mostly about eye shape what is it that causes it to change over time? My prescription keeps changing, the axis is pretty close through the history, but the cylinder number keeps getting larger each time by a tiny bit, and ironically the sphere is either 0 or close to it but also bounces around 0. I would expect if it was due to aging that my sphere would degrade as well. Why in the world would the shape of my eye change? I've read theories on it being due to muscles pulling on the eye causing it to get shaped differently but you didn't mention that.

    Secondly, in the section of the the video you show what astigmatism looks like for various cylinders and axis, but those aren't what mine looks like. Maybe I don't have an astigmatism or what you were showing isn't quite right. Mine looks more like a double of the image that is a bit offset from the other. Though it often seems to change even within the day I can notice it changing. Is what you showed astigmatism looks like for all? Might I have something different from an astigmatism? I wear glasses that have a prescription for Astigmatism, though I had to go back to an older pair as the new one my previous eye Dr gave me was causing a lot of achy sort of fatigue around the eyes. Though could just be me working on the computer all day. Been working on computers for 30+ years now.

    Third and last, for now, I've recently noticed that my close up vision has a similar doubling, though it appears to be in a different direction than the other. So for example for the distance to my computer screen and farther horizontal lines are close to perfect and vertical lines are doubled. But now close up the horizontal lines are doubled and vertical likes are close to perfect. Why would the distance change what axis my astigmatism is? That doesn't seem to make sense to me, but likely I'm not understanding something about how optics work. 🙂

    Thanks for making your videos, they've been VERY informative and I've been sharing them with others.

    Reply

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