Sphere, Astigmatism, Axis and The Eyeglasses Prescription
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- Опубликовано: 22 янв 2019
- A quick overview of the terms sphere, astigmatism, and axis; and what they mean relative to the eye and the eyeglasses prescription.
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This video was produced by Laramy-K Optical
Laramy-K Optical is a digital uncut and coating lab unlike any other. The only exclusively uncut lab in the country; we provide our customers with independent, high-end alternatives to corporate brands. Through craftsmanship, technology, and independent, innovative vendors like Younger, IOT, A&R, and Quantum Innovations we offer our customers the Integrity portfolio of freeform lenses and coatings. Made in the USA, the Integrity brand is not a generic house-brand, but is the absolute best available, designed to give the wearer that “wow!” experience.
In addition to the digital line, we still offer conventional surfacing, including glass. Maintaining traditional equipment gives our customers vastly more flexibility in their dispensing, particularly when it comes to more difficult prescriptions.
Learn More: www.laramyk.com
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I'm just a dude trying to practically understand why my vision is so terrible. This was extremely informative. thank you
Am an optometry student from kenya,your videos are really helping me sink in optical concepts of the eye ...keep it up
Newly hired optical tech! This was great info!!
Thank you for this video! I just got a job in an Ophthalmologist office and I had trouble understanding this until now.
I just wanted to thank you for being such a huge help to me! I’m studying for the CPOA. I’m currently a tech that works up a pt, scribes, etc, but I don’t have a hand in much of the optical side of things. THANK YOU THANK YOU THANK YOU! Happy I found your channel! The video most helpful to me so far has been the optical cross one.
You are welcome, welcome, welcome!
Finally, somebody who can give me an explanation that I can understand, everybody else wanted to give me the textbook definition but this was so much more helpful.
John,
I had surgical peal on the retina of my right eye several
months ago. The eye is now stabilized enough for new glasses. The optometrist
was crisp and clear. “You have an issue with the retina and slab off corrects
it.” My work with the Amsler Grid tells me that. Your video on that actually
explains what is really happening.
She also said I had an Astigmatism. What is that? “A
distortion of the lens.” Okay. Now I know more.
From a patient, thank you.
Rex
You are a perfect teacher- God bless you for this wonderful Video.
Thanks! This video really cleared up my perspective on astigmatism!
Best, Superb,Clear, Simple & Sweet Explanation... Thanks Sir...
Thank you for explaining it so I can understand .
Thank you for your time and knowledge
Phenomenal teaching! ❤
I have an astigmatism in both eyes. I recall 25 years ago, an optometrist showed me what it is that I see, and what I could see, with my eyes corrected. He demonstrated this to me using an Asterix. I couldn't believe what I saw. I thought it was a magic trick.
That was my first pair of glasses. Every pair that I have had replaced since then, have always been difficult to get the correct prescription! This is so frustrating. I often feel guilty telling them that I cannot see with the new glasses. I have always been told by the person that is selling me the glasses, "try them out for a couple weeks, they will be good for you!" I don't think they understand!
It would be excellent if the students would be able to see what a person with astigmatism sees! Then having a corrected prescription on top of that. Then shift that prescription (lens) just a little bit , so that they could see that the slight turn of the axis can affect one eye or the other.
It truly is very frustrating😠 for me. I also forgot to mention that when I get my glasses, I crazy glue the screw in the arms . This prevents any shifting whatsoever. My arms on my glasses are never folded. 🤓
I have astigmatism and I came to know about it after 24 years, I went to doctor I got -1 in left & -0.5 in right eye, My friend also have glasses for his eyes of same number ut his is Spherical so I put on his glasses & I really cannot read anything written a little far but when I took off his glasses I could read it. I was really afraid of it but now I understood the concept
I just came across your comment. My suggestion is to have them measure the OC height along with PD. That may help. Just something I found out recently that I think will help me. I am not an optician though so maybe ask your doctor.
I'm having the same problem right now with my new glasses. 😒
It's common for a lot of practices to dispense single vision glasses centered on the horizontal line of the lens. If your astigmatism is significant enough, standard fitting would end up being blurry if your eye doesn't sit exactly where they centre the lens.
I would typically avoid this by being careful with frame selection and then ordering a surfaced lens that I take accurate vertical and horizontal fitting measurements for.
I have myopia since 2009 and all the doctors at eye dept, or staff which take eye sight readings are in such a hurry that they never do it propoerly ... I am never satisfied with their readings because it causes strain and watery eyes ...
Optometrists dont care enough and just try to get the eye exam done in the shortest time possible.
I am unable to decide which lens's view is better, when they place metal glasses on my eyes and keep on changing lens on it ans keep asking me, "is this lens better than the previous?" they all look same ... And eyes get tired and its not possible to differentiate b/w - 2.5 and -2.75, cylinderical -1 or -0.75, axis etc
Thank u so so much i wana cry i finally understand been searching all day. My prescription changed so so i thought i need to understand. I doubt my opt. Checked probably.
God bless you! I have a prescription that has been wrong twice and I’m trying to figure out why my new eye doctor isn’t prescribing the right contact prescription. I don’t blame him, as when I’m in the exam room, I’m the one picking the lenses and telling him I can see. It must be something I’m doing wrong! I haven’t watched the entire video yet, but I’m going to binge as many as I can until I can figure it out!
Same - There should be a way we can test the lenses and walk around before exiting the exam. My brain's reaction to the lens are far different when I'm actually out in the wild with them.
Same problem with my new glasses
Great video. Thanks for all the content.
Great teacher, thank you
So helpful as an licensed optometrist in training,thank you!
Good.
You are helping me get out of myopia!
extremely well explained !
Couldnt say it any better!
this video is practically helpful thankyou
Great job. Thanks.
We love you and laramy k
And I love you back!
complimenti! Ottima Lezione :D Grazie!
Brilliantly explained
This video was helpful for my new contacts thank you I appreciate it !
Thank you so much for sharing your knowledge. Im going to tell the opticians thats been helping me with glasses about your youtube. I went back to the dr and another dr saw me today. He rechecked my eyes and came up with a completely different prescription. This video helps me to learn more about my sphere and axis , astigmatism.
You are welcome. John
Thanks for this video.. The more I watch your video. The more I starting to get it.. I can't do well on my test.. I can't memorize..
Excellent video, very well explained, thank you!
Thank you!
Thank you a lot
Thank you so much
Very good
Hey! A couple questions if someone could answer them :) Recently I got a new prescription for my glasses and I noticed how high my 'axis' were (180 & 170), thus why I came to this video but i was wondering if a high axis makes your vision worse than what appears in the normal - and + numbers. I have -1.00's across the board but and my glasses feel perfect for me but talking to others with the same or worse prescriptions as me my vision seems to be a lot worse than what the -1's say. So to sum it up do the high axis numbers make my sight worse???
Axis is notation of position nothing else. Its value is a placement marker that has almost nothing to do with vision. 0 and 180 are actually equal. So nope nothing to consider there.
Great video. Thank you
Glad you liked it!
Thank you sir ♥️👌
Astigmatism is not only occurs on cornea but there is also lenticular astigmatism which occurs on crystalne lens.
You are the best Professor Siegel! I did graduate my associate degree with the help of your videos. Now i am reviewing them for helping to pass my Practical Board Exam and get my NY license. Thank you so much !
I need me a mr. Potato eye . Amazing video. Very well explained!
greatvid
I've stuck with my old pair of glasses for decades because there aren't opticians able to measure my eyesight correctly. Too bad I couldn't visit your place of service, I really believe you could help with my eyesight problem.
No, I wouldn't and couldn't do that. Here in the US opticians don't perform refraction. If you can't find a human that can do it you now have some online options.
@@LaramyKOptical Would you point me to a few good online options? I've bought three or four pairs and they all give me severe motion sickness.
Wow!
I'm on a quest to learn how to explain to my optometrist exactly what is wrong with my astigmatism prescription. I know the axis (75) is a little off because everything is tilted a little counterclockwise. It doesn't bother me outside since there are few vertical lines to reference. But it's impossible to ignore when viewing the computer or TV. If I can determine that things appear tilted, say, 5 degrees ccw, I'd be willing to buy a cheap pair of online glasses with this adjustment, just so I'd be better able to communicate with my OD at my next visit. I just can't find out in which direction this would alter my RX of 75, and if there is a 1 to 1 relationship between the offending tilt and the RX. I will now check your other videos.
I can't really say that I've heard of any relationship between axis and tilted vertical lines. Certainly worth experimenting a bit. Just by the absolutely roundest pair you can get, mark the top dead center of the lens as they arrive as a reference and then loosen the screws and rotate the lenses and experiment. Might be a problem with the lens surfacing in that new pair over an axis issue? What is the cylinder amount? If your new glasses don't work, why not bring them back?
Got my eyes checked a couple of days ago- sphere right 0.75, left 0.50.
cyl .25 in both. Axis right eye 043, left 171.
Years ago, my left cornea got a deep hole in it do to an injury. It healed well but could that be a reason the axises of my eyes are so different? Thank you.
Axis is nothing more than a notation of position. Its value is meaningless. Could be anything from 0-180 with 0 and 180 being equal and 2 and 178 being basically the same. With that 0.25 cylinder you could rotate those lenses around 360 degrees and never even notice. Don't worry about it!
Clicked on this video first , trust the man with the scale model of an eye.
Don't let me down, shhh movie starting.
LOL
Hello, Sir!
Your videos are of the most helpful videos on optometry!
Would You please explain why is the lens positioned perpendicular to the meridian we are trying to correct? And if You have covered this confusing topic, would You please link the video!
Thank You!
If a lens is a sphereo-cylinder then it is trying to correct for two different meridians. Those two are (roughly) 90 degrees apart. So total power in one meridian is for one correction, total power in the one 90 degrees away is for the other. Maybe the video on the Optical Cross would be a good place to start. Then 30/45/60 and then % and then PIOMF.
Good info. Why do these numbers keep changing as time goes by? Thanks. Also, if I look at an object in a far distance without my glasses, will that relax my eye muscles?
Age and growth but they don't always change my own have been steady for nearly 30 years now.
From a Google search: When the ciliary muscle is relaxed, the choroid acts like a spring pulling on the lens via the zonule fibers causing the lens to become flat. When the ciliary muscle contracts, it stretches the choroid, releasing the tension on the lens and the lens becomes thicker.
Great video! Is it optically possible to make multi-axis eyeglass lenses for eyes that have astigmatism in multiple axes? I have keratoconus and see triple vision out if my worst eye. Even scleral lenses don't completely get rid of the triple ghost images.
Sadly it doesn't work like that. Even an eye with very, very basic astigmatism is not two perfect distinct curves. An eye with keratoconus is like a jagged mountain peak with rough edges. So nothing to match a lens curve to in order to make things better. Sorry.
@@LaramyKOptical thank you for the reply. Does this mean that even for very very basic astigmatism, 100% crisp correction of the image is usually impossible with eyeglasses? Even with basic astigmatism there will still be some amount of double vision or fuzzy / smeared edges?
@@LaramyKOptical Sir,I am using cylindrical lenses glass in left eye,still it looks a little blurry and one corner is clear.Is it normal or I should recheck ones?
He knows his stuff..more than a lot of opticians
Nice
For eye testing, patient have to sit 20feet (6mtr) away from the chart or place the chart just behind the patient and place a mirror 10 feet (3mtr) away from the patient.
But in my case, clinic room was small. There was fully digital setup, i.e., digital Phoropter and a small illuminated digital boxy screen which was only around 8-9feet (2.5-2.75mtr) away from me and there was no mirror used.
Is this distance adequate and will it negatively effect on accuracy of the prescription ?
As I understand it the modern "digital" equipment can overcome any distance issues. But - that is a bit out of my area of expertise. To some extent I guess I'd let my spidey-sense tell me if it felt right or not. Are we talking about a small exam room with matching modern equipment that looked like it had been installed correctly? Or are we talking about a converted janitor's closet with some mismatched pieces and some duct tape? We are certainly entering the world of VR exams where the distance will be a few millimeters!
Hello doctor my refractometer shows 3.0 on left Nd right and so the doctor prescribe 1.50 for me bout I still get stress should I go for 3.0 or 2.5
No doctors here... Always wear the lowest power possible that works for you.
How do you measure axis and sphere of the eyes wanted to import spectacles but I only have the measurements given by my optician which is -4.00 both eyes DSTJXMAR
-4.00 both eyes is just fine. Not everyone has the need for axis and cylinder.
Thank you for the video. I have a question. My current glasses are -4.5 both, no astigmatism. 6 months ago an ophthalmologist wrote a prescription for -5.25 both eyes, and both eyes have some astigmatic (cylinder/axis) numbers. I am about to order glasses online and they take your word regarding prescription. I wouldn't like to jump to -5.25 from -4.5 that I currently wear (I think i can see all right), I think its gonna be way too strong. I am 47 and I assume I should become less nearsighted as I age.. So if I change myself spheres to, for example -5.0, do my cylinder/axis numbers stay the same as the ophthalmologist prescribed? In other words, are cylinder/axis parameters independent from spheres (strength)? Prescriptions are only covered once a year. thanks
Whew - that's a bundle of stuff! Short answer is: If you are wearing -4.50 spheres and you are perfectly happy with those powers (you see great) then sure just online order another set with -4.50 spheres. BUT - once you get into astigmatism correction (cylinder) things get a little weird - but - short answer is you would leave the cylinder and axis unchanged if for some reason you wanted to lower the sphere power. You don't mention cylinder power but anything under 0.75 (0.50, 0.25) is negligible/unnecessary in most cases. And yep - at your age changes in power will start to give you trouble at different ranges, eventually 90% of people end up in a progressive or multiple pairs. John
@@LaramyKOptical thank you so much. Yes the cylinders are +0.25 069 axis on the right and +0.50 135 axis on the left. Decided to leave them off for now
Does Oakley make rX glasses and sunglasses to correct astigmatism?
I'm assuming you mean, "Does Oakley make wicked, cool, wrap, color specific golf lenses for their frames?" That will all depend on the lens power and amount of astigmatism. Quite low, sure even the crazy stuff can be done. Once you get past 1.50 and almost any cylinder the "sport" lenses get compromised. Oh, they will say they will work great and charge you a gazzilion dollars for the lenses but they WILL BE compromised when compared to a lens without the excessive curve/wrap. Inserts are an option but that gets fussy real quick. Contact lenses are the way to go. And then you can just buy your Oakleys off the rack at the pro-shop and hit the links... John
Thank you ! At 85 degrees per video. Looking at person. That would be slightly right of vertical. When transposed the axis is 175 degrees which is close to horizontal. When speaking of the physical location of the steepest curve is it with the axis at positive or neativ format. Thank you. Any place to reada bitout positive vs negative cylinder as it relates to looking at some one straight on
If I understand your question --- in minus cylinder form (lenses today are made in minus cylinder construction) the axis is the shallower of the two curves.
Thank you for your patience. In the video the steepest curve of the cornea is at 85 degrees. I was trying to visualize the curve on the cornea from a prescription. An optometrist will write in negative cylinder and an ophthalmologist will write in positive cylinder. The axis numbers will be 90 degrees different but the curve on cornea remains in the same location. Trying to visualize on my friends eye where the steepest part of the cornea is from a prescription not necessarily how a lense is created to correct vision. One writes prescription as 85 the other 175. I understand 0 to 180 counter clockwise in pictures of eye on line. Thanks for the help.
@@williambauer6181 The choice to write in + or - cylinder form is down to preference. It isn't OD or MD. The curves on the cornea are read using a keratometer which provide K readings which can be read as curves for fitting contact lenses. The refractive error created by the cornea is considered when fitting eyeglass lenses, the curves of the cornea are not. Depending on what the error might be it isn't always a case of weaker/steeper. I applaud your visualization exercise but I can't help much beyond that. To know exactly the relationship between your friend's lens powers and cornea you would need a keratometer and the lens "Rx" and a doctor willing to explain it. My examples are very general or conceptual not specific.
i dont understang how to cut lens with axis 30 way? cound i see where video about it? thank a lot
See: OpticianWorks.com.
Hello Doctor, very Nice Video, Thank you so much, I got a doubt If we got spherical power - then eye ball size is increased ???? and if we get cylinder power then we get change in cornea shape ??? pls explain the anatomy of eye related to spherical and cylinder power problem, pls comment i need this information urgent, if u make video then its great because videos are not available, Thanks in Advance
It can be a combination of those two. You can have an eye shape that creates the need for correction WITH a cornea with a shape that creates the need for correction. It isn't necessarily one or the other. But - yes I guess you can think of astigmatism and the need for cylinder as being more corneal related over length. And yes if it is just a matter of length then it can be corrected by lenses with spherical power.
@@LaramyKOptical Thanks for your reply 😍, Is there any instrument to measure a Eye ball size and also for corena size, shape
@@ALLINONETrending Nothing that I know of for length but the keratometer measure corneal curves. There are manual ones and auto ones. They are used to fit contact lenses. Powers for eyeglass lenses come from refraction or auto-refraction and are not based off of corneal curvature but where light falls on the back of the eye. Seems like you might be over-thinking it all a bit.
Can astigmatism be caused by smart pH one use
Astigmatism is a condition in which light scatters in the eyeball which does not concentrate on the retina, the lens/focal power that correct astigmatism is referred to as "cylinder", just like lens that correct myopia is "sphere".
sir tell about alignment of rimless frames with bracing pliers
Just that --- it is a brace and bend technique. Hold the mounting point with the pliers (working from the top) and then bend the part with your hands or another tool. You are isolating the part so you are only bending it NOT the lens in any way. You could always take things apart, bend and put them back together --- if you absolutely had to that is.
Great video. Can I ask one question?: If an optometrist gives me two different single-vision prescriptions, one for distance and one for near/computer work, should the cylinder and axis be the same in each prescription (right and left eyes, respectively)? I.e., cyl and axis are independent of sphere, right? Or am I misunderstanding something?
99.9% of the time cylinder and axis will remain the same. Only the sphere values will be different. I have seen a few times where a doc will drop the cylinder a little as well but very uncommon.
@@LaramyKOptical Thanks a lot. The cylinder is the same on both of my scripts. I think the difference in axis (130 vs. 145) on my two new scripts is most probably yet another mistake from this incompetent optometrist office. (Long story, but both scripts were revised recently after the glasses were unwearable after the first exam.)
@@WillfulThinker Just keep in mind if cylinder is 0.25 or even 0.50 axis is almost meaningless. But it sounds like you have sorted things. John
Is it possible for people with cylindrical lenses in their glasses to have peripheral blurring of vision? Since the axis of the cylindrical lens is aligned with the axis of the astigmatic eye is it possible that they may not see so well in other directions than straight ahead?
Absolutely! All/any lens can create blur as you move away from the lens optical center. Add in cylinder and you increasing the chances.
@@LaramyKOptical thankyou!
I have a pair of prescription progressive glasses that the right arm is broken I ordered the exact replacement frames and would like to install the lenses myself. The lenses are Height:52mm Lens Width:52mm Yes the lenses are perfectly round do you have a video demonstrating the proper way to mount progressive lenses that are perfectly round?
ruclips.net/video/E1s9zZM2JPU/видео.html
It will all depend on you keeping track of things BEFORE you take anything apart. If you mark up the lenses BEFORE you take things apart and reinstall them in the exact same position you should be just fine. Don't forget R and L and a direction arrow. Progressives do have laser etchings you can see under very bright light and these can be used to reposition things if they should get screwed up. You Got This - John
@@LaramyKOptical I forgot to mention that these lenses are
Zeiss Glass High Index would you recommend using a AR pen to mark them?
@@ke4uyp I'd actually go with some painters tape and then a ball point or an AR pen. If you try to mark directly on the glass you are far more likely to wipe off or smear your marks.
What is the meaning of UN 6/9 in prescription ? plz answered
en.wikipedia.org/wiki/Visual_acuity
Average person here just wanting a better understand of what my numbers mean on my contact lenses. Thank you!
Is there an acceptable range in the optician world to have a prescription minority off with CYL and Axis?
Yes. The industry mostly works with ANSI standards. John
I have keratoconus. Thank you for this simple explanation
You are welcome.
Hello! Do you have any videos about finding the true powers?
Tina, I'm not familiar with the term "true powers."
@@LaramyKOptical I am studying for my AbO exam and it has a question like what are true powers of this RX or true power of the lens at 180. Do you have any videos of that?
@@tinaswearengin3062 Absolutely no idea. As to power in any given meridian, yes, plenty of videos on that. Optical Cross, 30/45/60 % rule and the power in oblique meridian formula.
@@LaramyKOptical Thanks!
Hello, could i please get your opinion on my son's recent eye prescription?
My 16 year old son recently had his eye examination done in Aug 2022 with an OD of -3.00 and OS of -3.75, with a cylinder of -1.00(Axis 23) for right eye and a cylinder of -1.00(Axis 162) for left eye.
A year ago in May 2021, he had the same OD and OS, i.e -3.00 and -3.75 respectively, however with a cylinder of -0.50 for both eyes.
So with the same sphere for last 2 prescriptions, and only a change in Cylinder, shall we go and have new glasses made with updated Cylinder of -1.00 ??
Or keep the old glasses , same sphere but with cylinder of -0.50? Will a cylinder of -0.50 make his vision worse if we don't update it to -1.00 as per the new prescription?
Please clear my confusion.
I'm not a doctor just an optician so this is my OPINION: At 16, a growing boy, I wouldn't be at all surprised to see a 0.50 increase in cylinder. Assuming a good refraction he will probably see a little better. I don't believe much in wearing glasses making things better or worse - especially with small changes like that. For what it is worth at his age and those powers he might want to try contact lenses! (Where he would probably wear a simple inexpensive sphere.)
@@LaramyKOptical Thankyou so very much. If i correctly understand , what you are saying that with a cylinder increase from -0.50 to -1.00, he would probably only see a little better, and with small changes like this doesn't matter much. In other words, we can stay with the old prescription and it won't make his eyes worse, nor the new prescription with same sphere and a little increase in cylinder will make his eyes better, right?
Honestly, i don't have any idea about Contact lenses as my son has been wearing glasses for almost 7-8 years, but yes he can try contact lenses, if that can help improve his vision and make his eyes better compared to glasses?
The right type of contact lenses, is also something which i am completely unware of and the maintenance.
Could you please advise. Thankyou,
@@Sana-rz1ho Again - People will believe what they will. There is no scientific proof that wearing glasses causes any "weakening or strengthening" of vision. You may read otherwise and what you decide to believe is up to you. I am willing to bet that your son would struggle getting through his day without vision correction. When he puts a lens in front of his eye he sees better. He chooses which is better 1 or 2? If in the end it is 1 and that is the new lens power then chances are he will see better when he gets the updated lenses. My contact lens suggestion is one I would make to any parent of a teenager. There are many advantages to contacts including teenaged self esteem issues. If he plays any sports then it is almost a necessity.
@@LaramyKOptical I like your wisdom. Thank you so much.
As far as his old glasses(with same sphere as of new) execpt cyl of -0.50, he never complained about vision.
Now with the updated cylinder of -1.00 and identical spheres in the new prescription, i will go and have the new prescription made in order for my son to see better with improved cylinder.
Yes, he does play sports(Soccer, tennis etc), all with glasses so far, as since i didn't have any idea of contact lenses, i never thought about it.
But now, i will have to see which contact lenses need to be made of his age, which he can take care of as i have doubts , if teenagers get hit directly in their eyes and wearing contact lenses or any object like a tennis or soccer ball get hit directly in their eyes wearing contact lenses. So i am confused :):)
@@Sana-rz1ho Yes, contact lenses do require the combination of motivation and responsibility - but - you might be surprised and they do make disposable contact lenses now. Maybe he doesn't live in them but wears them for sports. As to safety I guess you go with whatever the team/school/league whatever says is required. Most athletes prefer contacts over glasses for the increased peripheral vision and no-fogging. Sure some people wear a safety sport goggle some don't. Maybe ask around a little - maybe some other parents have had a great experience with a local doctor and contact lens specialist. And all that means is a person that does a lot of contact lens fitting and insertion and removal training - it isn't some high level costly specialist!
I have myopic astigmatism simple with amblyopia in right eye..and I still don't understand it😅....can you explain a bit🙏
Myopic means that yoyr vision is better at near than far , the light insteaed of gathering on the retina gathered before the retina , minus lens fix myopia.
Astigmatism means that the light gathered in more than one point , thats why you see blur .
Amblyopia means (lazy eye) , we cover the other eye so the lazy eye do it work .
Sir, I have an important question, which design is more comfortable and good to patients, Positive or negative cylinder
No such thing as positive cylinder. Only lens powers written in + cylinder form. Modern lenses are all minus cylinder design. See the video from 2 weeks ago on cylinder.
Thank you sir, yes I meant + or - cylinder, but I have got advice from expert optometrist I should trans the mixed eye to + cylinder which is comfortable as a spectacle lens
But one doctor told me the - cylinder preferably and comfortable to patients !!
@@sadeqajeena How you write the powers on a lens has absolutely nothing to do with wearer comfort. It is the exact same lens. Write your lens powers in the form most common for where you work.
Appreciate your answer, thank you sir
I have a VERY mild astigmatism in one eye, but it really gets on my nerves when I'm doing detailed work or in low light. Should I bother trying glasses? +.50 CYL. -0.75 x 125
Yes!
No!
Maybe!
0.75 is just about where a human can "perceive the need" shall we say.
That +0.50 would help with close up work so that combined with the 0.75 cylinder it might be worth giving a pair a try.
No store-bought readers will work.
Might be a good test for one of those online places. [Just use 62 as a PD]
If they help then hit a real store and get a good pair made up just for you.
@@LaramyKOptical Thanks for your reply! My PD is 66. I’ll give them a try and see how I get on...
Does the axis change due to age? Mine just changed a lot since my last exam 3 years ago? Is a changing axis a sign of anything to come?
Usually just by a few degrees one way or the other. Don't confuse the two different ways that "prescriptions" can be written. Then the axis may be about 90 degrees different yet the same.
@@LaramyKOptical Thank you!
Question: my old eye prescription (2 years old) from a Lens Crafter optometrist has the sphere at about -2.00 for both eyes. I recently visited an ophthalmologist and I was told that my eye prescription ( taken from my old glasses) hasn’t changed. From their prescription, they have the sphere of both eyes at -5.00. What’s up with that? Great video btw! Oh, I can wear the same old glasses! 😎
Well, -5.00 sure ain't -2.00! I'm not sure who is thinking and saying what or why.... Are you sure you're not getting cylinder form mixed up? Does the lens order have a sphere, cylinder and axis?
@@LaramyKOptical Ok, here are the 2 prescriptions. See if you can figure this out. From 11/12/2018: R -2..00 x -3.50 x 178 L -2.75 x -3.00 x 172 (done by an optometrist). From 11/05/2020: R -5.50 x +3.75 x 85 L -5.75 x + 3.25 x 85 (done by a tech at an ophthalmologist's office). I got new glass with the 11/05/2020 script and I see perfect as i do also from my old script. I was told by the tech that my new script was almost identical to the one done in 11/12/2018. From the new script, I see the AXIS is way different. Let me know what's up? Thanks.
@@razziade ruclips.net/video/rVMW5a6qJ6I/видео.html
@@LaramyKOptical Ah...I understand now. I like the first way better. The numbers are smaller and makes me think my vision isn't that bad. Thank you for a quick reply!
Broken Retinoscope.
I was always told it was the shape of eyeball itself was what made astigmatism. What is irregular astigmatism?
No idea.
Q1. Sir please resolve my query.
If we reduce the cylinder value in prescription, will axis remain same or it will also changes by some degrees like 10°-15°?
for eg., if we reduce cylinder from this prescription -1.00/-0.75 axis_35° (left eye) to -1.00/-0.50, what would be the new axis-?
Q2. Eye testing computer machine (Auto Refractometer) in optician shop give this reading :-
-1.00/-0.50 axis_161° (right eye),
-1.00/-0.75 axis_38° (left eye).
And the optometrist of the shop give this prescription by using digital Phoropter device and digital display chart :-
-1.00/-0.50 axis_160° (right eye),
-1.00/-0.50 axis_20° (left eye).
Why he reduced the left eye axis from 38° to 20° but not the selected nearby axis like 30° or 25° ?
Isn't 18° cylindrical axis variation is high and outside the safe tolerance limit ?
[ Few days ago, I also checked my eyes from the hospital, and their auto refractometer give -1.25/-0.75 axis_37° (for left eye) and the doctor gave prescription -1.25/-0.50 axis_30° (left eye). ]
Everything is fine. It is not unusual for axis to change or be interpreted differently by a few degrees. Axis is a notation of POSITION nothing more. And with just 0.50 (negligible to almost unnecessary) it would be far more likely things would vary. There literally isn't enough power there for the instruments or you to decide spot-on. If it was 5.00 then it would be a different story. John
@@LaramyKOptical please answer to my first question in more detail.
@@Sidg2 There is no relationship between the power of the cylinder and its position beyond what you say it is. [and the actual shape of the cornea] The phoropter has the ability to rotate the axis/cylinder position with a swing of 180 degrees - YOU are the one who says 1 is better or 2 is better as the doc switches between the different positions. Again - with that kind of cylinder power it really doesn't matter. You could swing that lens back and forth 20 degrees and may well not be able to perceive any difference at all. Heck you may well be able to take out the cylinder and be just as happy. Or of course the opposite where you miss the higher cylinder you had before and would prefer to go back to it. It is mostly perception and not any direct 1:1 relationship between anything. Perceived lens power(s) vary by tilt, wrap, distance, material...
So if my axis use to be 170 and now it’s 010 do I have to get a new pair of glasses?
Yes, No, Maybe, I Don't Know... What is the middle number or the cylinder in your lens power? The difference between 170 and 10 is 20 degrees. 0 and 180 are the same for lenses. Less than 1.00 cylinder and you might be just fine. More than 1.00 and it would probably make a difference. John
The 170 cylinder is -2.50 and the 010 is -0.75
Kristen. I'd need your complete prescriptions both the old and the new to help.
Laramy-K Optical OLD OD sphere +1.75 cylinder -1.75 axis 170 OS sphere -0.25 cylinder -1.00 axis 170 NEW OD sphere +1.50 cylinder -2.50 axis 170 OS sphere -0.75 cylinder -0.75 axis 010
R. eye Sph 9+00 cyl 1.50 axix 170
L. eye Sph 9+00 cyl 1.50 axis 10
I hope you are fine doctor please tell abut laser is it possible for me or I need thick glass so please inform me sir thanks
Steepest curve? How's it 85 degrees...looks like a lot less off center than 85%?
Well that explains my 001 vs 179 axis 🙃
I feel nauseous after I just got a new prescription and glasses. Why? They're a little bit stronger than my last pair, but with different Cylinder and Axis values,.
No way of knowing for sure - but it sounds like you have already figured it out (maybe). If power went up (even a little) and axis changed you may be sensitive to that. A change in axis of a degree or two is normal. A change of axis of 90 degrees is just different way of writing the power. A change of +/- 5, 10, 15 would be suspect. Take your old and new to an optician you trust and have them do a comparison. Any optician worth a darn should be more than willing to explain the difference(s) to you and that would give you a place to start. Have you gone back to where you got them and asked them to check them?
@@LaramyKOptical The glasses I've worn for years are:
O.D. -7.75 Sphere, +.50 Cylinder, Axis 10
O.S. -8.25, Sphere +1.00 Cylinder, Axis 170
My new Prescription is:
O.D. -8.50 Sphere, +.50 Cylinder, 106 Axis
O.S. -9.00 Sphere, +.50 Cylinder, 89 Axis
Pupil Distance 61
I'm literally going back tomorrow to recheck the refraction. The ophthalmologist doesn't do the refraction. The assistant does it. Thinking of getting another eye exam somewhere else possibly.
@@Professor5180 Watch the video on Flat Transposition. It almost looks like someone did that and did it wrong. It can happen. Those axis look awfully close to being 90 degrees off. Almost willing to bet on it.
You say that astigmatism doesn't change? It is what it is, but why are mine changing and only one seems to be tolerable and more relaxing than the others and more free of migraine. My Rx changes a lot in general from one doctor to another.
It can definitely change as you age
hand neutralization of sph,cyl lr
ens
Sorry but never going to happen. I see no practical application for it in the day-to-day working life of an optician. We have so many things that are far more important and useful that need to be taught. John
Why are there two different powers (i.e. red and green) in one eye? Doesn't one eye only have one power? My axis changed over 2 years from 40 to 140 and I'm concerned it's an error.
You'll find several other videos that explain how lenses correct vision on the Laramy-K OpticianWorks RUclips channel. Many eyeglass "prescriptions" correct using lenses with two different primary powers. A change of axis from 40 to 140 (depending on the cylinder value) might actually be cause for concern that something was done wrong/entered wrong. Unless the one prescription was written in minus cylinder form the other in plus. John
@@LaramyKOptical Thanks John! I think so too, here's how it reads for 2023: OD Spherical: -1.75, OD Cylindrical: -.50, OD Axis: 140. OS Spherical: -2.25, OS Cylindrical: -.50, Axis: 36. I'm 32 and in 2019, my cylindrical for both was -.25 and Axis for both was 40. Do you think the 140 is supposed to be 40 for 2022? Spherical has improved slightly so I'm not as concerned about those numbers nor the cylindrical based on what you just wrote. thanks so much for the insight.
@@faynenicolemascarenhas5213 With 0.50 and 0.50 a difference of 100 degrees really won't make much difference at all. Because of surfacing techniques you can get 0.25 cylinder from a spherical lens. If you see a little better I wouldn't give it a second thought. If those middle numbers (cylinder) were -5.00 then we would be very worried. I suppose it is always worth asking to see exactly what the doctor wrote on his exam form. Common mistake is adding 100 to an axis. But I'd say you are pretty safe.
Thank you this has saved me a lot of heartache, my doctor was very upset with me so I am nervous to clarify and was also nervous he miswrote my rx intentionally. I’ll just go with the 40/36 for axis and -.25 for cylindrical on both. These videos were also very helpful for me to understand the concepts. So grateful to you and your team for these!
Memories is hard for me.. What to do
Rewatch video 500 times
Can anybody please tell me if 90 degree and 85 degree eyes are ok?Do we call it astigmatism or eyes are normal?
90, 85, 123, 0 doesn't matter. It's just a position marker for a curve on a lens.
@@LaramyKOptical Sir thanks for replying.So it does mean that if the 2 eyes axis are close to each other then its all okay?90/85 degree is not a problem at all?
Sir ,the video was not properly visible .
When you say "Correction", does it mean the cornea "heals" and becomes round?
Goodness no. Correction of the light by the use of a lens so it hits where it needs to on the back of the eye. LASIK (sort of) does the correction of the cornea.
@@LaramyKOptical I see. Thank you for clarifying!
I have a +6 diopter astigmatism in my good eye
That is quite a bit!
Anyone else here because they just got a new optical prescription?
A lens is spherical, so how does turning it 85 degrees change anything?
did you not watch the video?
Do people with astigmatism get myopia as they get older?
Not necessarily - certainly not a given. There are a few other videos about refractive errors and refractive errors and how lenses correct them.
If i have a Rx 2.25 -0.25 x 90 does that mean axis 90 i have power 2.25, axis 135 i have 2.125 axis 180 i have 2.00? so if my Rx went from 2.00 (no cyl) to 2.25 -0.25 x 90 i would only have a 0.25 change in Rx?
Correct if you went from a 2.00 sphere to a 2.25 -0.25 you would have a change of 0.25. That work for you since you are plus. John
@@LaramyKOptical would it be identical if the sph was -2.00 then -2.25? (same cyl) ie still a -0.25 change?
@@Zeugenschutz ruclips.net/video/Z-f0k6p2W-w/видео.html
Google searches show, the entire eyecare industry in the US, if not the world, cannot clearly, professionally interpret the eyeglass prescription rules. It's so confusing, inconsistent, even contradictory. While this vid is exceptional in explaining astigmatism using models, it didn't even touch how this is related to the Cylinder values on a prescription, why it's positive or negative...
Nice video, but holy crap, could someone of the hundreds of videos, blog posts and optometrists websites PLEASE explain what is the dang "Rule" that Against-the-rule and With-the-rule refer to???
Since contact lenses are fit to the front surface of the cornea WTR astigmatism is a contact lens fitting term. Crazy simple way of thinking about it - just think/look at the shape of the eye (opening in humans) and in almost all cases the eye is steeper along the 90 than along the 0-180. Our human eye appear longer (flatter) at 0-180 than it does when it is "open" along the (shorter) 90th. So the "rule" is that you will assume that if an eye is astigmatic it will, in all likelihood, be steeper around the 90. You also assume that as a reference point for LARS when doing a toric contact lens fit. Plenty more on that on the OpticianWorks website. John
@@LaramyKOptical thanks for your reply. I gather that you're saying that the "Rule" refers to "as a general RULE, astigmatism features the cornea having smaller radius of curvature in the approximately vertical (90 deg) direction", right? Though from other reading, it seems this "general rule" applies to younger people, and not so much to older?
"
@@Graham_Wideman Yep - I'd say that covers it. Never heard anything about it being age specific. Most people don't start wearing contacts lenses until they reach teens or beyond. And - again it is a contact lens term and concept with no practical application(s) beyond that. It is about the fit of contact lenses - it is not about eyeglass lenses, vision, astigmatism correction or any vision therapy stuff. I kind of have the sense you are looking for answer to a question that isn't there?
@@LaramyKOptical thanks again. Google easily finds many examples of with/against
the rule used to describe astigmatism, not just lenses. Likewise google finds references regarding age-related changes toward "against", including papers on pubmed.
130 degree in right eye n only 30 degree in left eye...Is this possible .. ?
Sure! Degrees are just notations of position, they have no value. Could be anything from 0-180.
@@LaramyKOptical
Right eye. Left eye
Sph. - 0.25 + -
Cyl. - 0.50 - 0.50
Axis. 130 degree. 30 degree
Contact lence. 31mm. 31.5mm
@@bboyrinku9 Like I said, sure! (you will have a hard time getting a contact lens to work)...
how old are you ?
104
😂does it affect the chances of you benefiting from the video?