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Likelenses 16 Aug 2016, 20:44

Cactus Jack

In two of the older books on ophthalmology that I have, { one is 1926,and the other 1960,and different authors },they both make a strong point that only perfectly round lenses are completely accurate in their prescription.


astigmaphile 12 Aug 2016, 19:53

Cactus Jack,

Thank you for the info.


Cactus Jack 12 Aug 2016, 18:52

Astigmaphile,

The amount of PLUS I need to neutralize the excess "MINUS" seems related to the amount of prism, but not absolutely. The 15/15 BO works pretty well with +1.00 contacts or clip-ons and the 23/23 BO work pretty well with +1.25 or +1.50. I have some 20/20 BO that don't need very much extra PLUS, at all. It is complicated a bit by apparent Induced Cylinder at the higher values. It may be related to the way the lenses are mounted in the frames which affects the angle of incidence of the Central Axis of Vision on the back surface of the lens.

Unfortunately, I don't know enough about lens design or have the tools to fully analyze it. Part of it could be the location of the Optical Center of the lens. Pure Prism Lenses do not have an Optical Center, but Spherical and Cylindrical Lenses do and the location of the OC is affected by the Prism and convergence or divergence of the eyes.

One really off-the-wall theory is that because a Myopic eye is elongated, when it is NOT looking straight ahead. the bony eye socket may press inward slightly on the back of the eyeball and reduce the distance from the Retina to the Crystalline Lens. Even 0.3 mm would REDUCE the required Sphere myopia correction by about 1.00 diopter.

As Yul Brynner said in The King and I, "is a puzzlement".

C.


astigmaphile 12 Aug 2016, 16:26

Cactus Jack,

Now you have me curious to know how prism could make glasses seem to have more minus than is really in them.


Cactus Jack 12 Aug 2016, 09:10

H,

It really was not rough. Before I got glasses, I had no way of comparing what I saw and what I should see. After I got glasses, I knew when I needed a prescription change and what to do about it.

Today, most of my vision problems are age related, with one exception, the development of Adult Onset Strabismus. I have Type 2 diabetes that I have managed, with good coaching, since it was discovered by accident when I was about 30. So far, no Retinal damage. Over the years, I have developed most of the other health problems associated with Diabetes. Fortunately, they were discovered very early because of the insistence by my Endocrinologist that I get tested for them. At 78 I can do almost everything I want to and a few things I don't particularly want to, but have to be done. The snag is that I am a walking Pharmacy, but it works. As the old DuPont advertisements used to say, "Better things for better living, through Chemistry".

My Adult Onset Stratums (Esophoria) is a nuisance because my eyes try to turn inward, very significantly, when I am tired. I need Prism in my glasses to keep images fused and even moderate Prism can cause optical distortion, in addition to doing its primary job. Another thing that exacerbates the problems with prism in glasses is that making glasses with prism is almost a lost art. Muscle surgery can fix many strabismus problems, but not all. Today, there is so little demand for prism correction in glasses that only a few specialty labs know how to make high prism glasses. Also, very few dispensing Opticians know how to order and fit glasses, with a lot of prism, for minimal distortion and best possible Visual Acuity.

From a purely vision point of view, my brain has leaned how to use both eyes simultaneously, under nearly all conditions. It seems like once my brain learns how to deal with different visual input conditions, it stores the "algorithm" and is able to call it up very quickly. However, there are limitations to the ability to fuse two widely separated images and double vision results. Base Out Prism in my glasses can move the two images into a range that allows my Eye Position Control System to command the eye muscles to do what is necessary to fuse the images, but optical distortion may may be more than the the brain can process and reduced Visual Acuity occurs.

One unexplained phenomenon that occurs, even with moderate prism correction, is that the glasses seem to have too much MINUS that can be corrected with supplemental low PLUS using contact lenses or clip-on lenses. The glasses will check perfect and exactly what was prescribed, but not have the VA I saw during the exam. I am trying to figure out why. I have a Theory, but right now, I have no way to prove or disprove it. The few ECPs I have talked to can't explain what I experience and describe.

C.


Soundmanpt 12 Aug 2016, 07:43

H

So unless they were advised to wear their glasses for more than just reading and seeing close up which could be due to their possibly having astigmatisms which effects eyesight for all distances. Otherwise they may have just decided that with as much close work they do constantly putting on glasses and taking glasses off was too much of a hassle, so they just leave them on most all the time now. If you were to get glasses that might be a decision you might need to make as well since your job requires a lot of reading and close work. At first i'm sure you would probably try to only wear your glasses as little possible But i'm sure you have noticed with your siblings that once they got their glasses they soon weren't able to read anything with small print without their glasses anymore. Please notice that I did say "If you need glasses" i'm sure you're hoping you are good for at least another 2 years.


H 12 Aug 2016, 07:14

Soundmanpt,

My older brother and youneger sister wear their glasses basically all the time. The rest wear them as needed.


Soundmanpt 11 Aug 2016, 13:44

H

Thanks for pointing out that Labor day hasn't quite got here yet so your correct that you're not past due with getting your eyes examined since you don't wear glasses and 2 years is the recommended time frame. Good to see that not only you but your husband and kid as well. So what are the wearing habits of your siblings? I mean do any of them wear their glasses full time or do they just put them on when they want to read something? I asked because you said your twin and brother showed up wearing glasses but were they just wanting to show everyone that too now wear glasses? All of them have jobs where seeing things close up is essential so it could be quite a pain doing much of the on and off thing. Your twins glasses should be weak enough that she might choose to just wear her glasses all the time if her distance isn't effected too much wearing them. Good luck Sept 2nd i'm sure you would prefer not having to wear glasses just yet.


H 11 Aug 2016, 12:48

Soundmanpt,

My twin was prescribed glasses. She said she had been having trouble reading, so she booked herself an appointment and ended up with glasses. As for it still has not been two years. The kids, my husband, and I have appointments for September 2nd.


Soundmanpt 11 Aug 2016, 10:41

H

Now that the last 2 of your siblings has started wearing glasses and one is your identical twin sister it would seem that you can't be too far behind. With your twin getting her first glasses i'm surprised she didn't ask you when you're getting glasses? Being identical twins you almost certainly should have the same genes for your eyes as her. Did you ask your sister if she went for an eye exam and was prescribed her glasses or if she maybe just bought a pair of over the counter readers to relax her eyes a bit. I wonder if she went for an eye exam because she was having problems with reading or if she had no problem and was only getting her annual eye exam and was surprised that she needed glasses? You all seem to have jobs where your eyes are likely at the very least being strained quite a bit. Next time you're around your twin sister you should ask to try her glasses and test your eyes by reading from a book or newspaper to see if they are relaxing to your eyes. You may find them to be more comfortable than you think. You have every right to be curious how or why you so far haven't showed any indication of needing glasses when all 6 of your siblings are now wearing glasses. Since it has been over 2 years since you last had your eyes examined you're actually due now for an eye exam. You wouldn't be the first person to go for an eye exam thinking their vision was perfect and come away being told they need glasses. In a way don't you feel left out anyway?


H 10 Aug 2016, 15:02

Cactus Jack,

Sounds rough. How is everything (vision-wise) for you now? Do you still struggle with getting your eyes to work together.


Cactus jack 10 Aug 2016, 05:49

H,

When I was in University, around 20 (1957).

I had natural mono vision, apparently for years, before it was discovered in my early teens. My first prescription, at 14, was OD Plano, OS -1.50. I was reading with my left eye and using my right eye for distance. I had very poor depth perception, but didn't know it.

That explained why I could not hit a baseball. By the time I figured out where the ball was, it was in the catcher's mitt. I got along fine with academics, math, and the sciences, but no school (or after school) baseball team wanted me for my ability to "walk" or "strike out". So I found other interests, the sciences and electronics.

Glasses forced my eyes to work together and focus together, but they did not particularly like it. The massive visual workload in Engineering caused bad headaches. I had to make a choice between buying aspirin by the case, flunking, or getting bifocals. I got +1.00 bifocals and that solved the problem.

C.


H 09 Aug 2016, 23:47

Cactus Jack,

When did you start to need help reading?


Cactus Jack 09 Aug 2016, 09:21

H,

Very few people are immune to Presbyopia. Just consider yourself very fortunate that you have escaped, so far.

Presbyopia actually starts in childhood, but doesn't become a nuisance until somewhere in the 40s. The BIG exception to that is if a person has uncorrected Hyperopia.

Hyperopia is the ONLY refractive error that a person can correct internally, using some of their Accommodation Amplitude (AA) (a measure of the range of their "auto-focus" system). People with moderate Hyperopia often do this without even being aware that they are doing so. A common symptom of low to moderate Hyperopia is exceptionally good distance vision. It is like a slightly over corrected Myope.

Because they are using some of their AA to compensate for their Hyperopia, Presbyopia often becomes a nuisance much earlier than the 40s, particularly if they need to focus very close. That is why many teens discover that they need close focusing help (bifocals or progressives) to read the tiny text on their smartphones. If they are lucky, they may be able to recover some of their AA by wearing PLUS glasses to correct their Hyperopia, which makes more of their accommodation available for close focusing.

May I suggest a few common events to look for in your study of Presbyopic behavior.

If they can wear non-prescription readers, the purchase of many pairs of reading glasses to scatter throughout their environment. (BTW, very low cost readers at "dollar" stores are not bad.); Use of a neck cord for their glasses to keep the readers very handy and difficult to misplace; The acquisition of stronger readers as their Ciliary Muscles become de-conditioned - until the get to around +2.50 to +3.50; Discovery of bifocals or progressives as being the face is the most convenient place for their reading glasses. Some even have no prescription in the distance segment; The ultimate utility of trifocals as being useful for distance, computer displays, and reading.

Enjoy while you can.

C.


H 08 Aug 2016, 21:11

Wow, it sure seems everyone around me is needing reading help now. Just today my co-worker showed up with some readers, and my cousin posted a picture of himself at wearing glasses to read a menue. I just thought it was a weird thing I noticed, and for some reason felt like sharing. After all this, I cannot help but think I am next.


H 07 Aug 2016, 22:36

Cactus Jack,

You won't. I understand curiosity. It is what led me to my profession. I don'y ant to stand in your way.


Cactus Jack 07 Aug 2016, 22:27

H,

Thank you for the offer. I will not abuse your kindness.

C.


H 07 Aug 2016, 21:32

Cactus Jack,

Well, who am I to stand between you and your curiosity. If you want to know something just ask.


Cactus Jack 07 Aug 2016, 19:00

H,

In your first post, you mentioned "my twin and younger brother showed with readers". Somehow, I construed that to mean three brothers. Sibling rivalries between adult bothers, regarding vision, can be intense. It can lead to very funny situations. It is a masculine thing. It is amazing, the lengths brothers will go to, to try to hide the need for vision correction. It is often much more powerful than female vanity.

I think I mentioned it earlier, but try to read "Macrae's Story" on the Vision and Spex site. Here is a link:

http://www.vision-and-spex.com/fantasy-and-true-stories-about-vision-glasses-f7.html

I think you will find it entertaining.

A little about me. I am 78. My background is Electronic Engineering and Computers. I am blessed or cursed with a very strong "curiosity bump" which is probably what led me into Engineering. From a very early age, I wanted to KNOW how all kinds of things work. I became interested in Vision and its correction because I was not pleased with the explanations I got from Eye Care Professionals (ECPs) when they could not explain why certain glasses prescriptions decreased my Visual Acuity rather than increased it. That made my "curiosity bump" itch. Because of the work I did, I really needed to see well at all distances.

I started doing detailed research on vision and optics and I guess I have become something of an Amateur, in the original French sense. If I had it all to do over again, I probably would have tried to study and do research in Genetics and Ophthalmology.

There were several things that aroused my curiosity about your family. Seven highly educated siblings with not one but two sets of twins, mostly in the medical field, who are likely familiar with role genetics plays in individual characteristics. The reason I asked about your family's visual history, is that there significant empirical evidence that genetics plays a very large role in visual development. For example: Why do some races have a propensity to be Myopic and others Hyperopic. Why does extreme myopia run in families. What hormones regulate Eyeball Growth?

There almost has to be a specific hormone involved, else why does becoming pregnant often cause an increase in True Myopia in a woman whose Myopia had stopped increasing?

In some ways, it may be like the difficult study that finally proved that tumors had the ability to force development of a blood supply, which may lead to a way to inhibit tumor growth. The story of how that hormone (?) was found and was proved to exist is fascinating. Also interesting, is that there may be another hormone (?) that can prevent other tumors, offspring from the original tumor, from growing - until the original tumor is removed. Then they have a field day.

Many years ago, I read an article about some research, done at the Johns Hopkins Ophthalmology Department, on the causes of Nanothalmia (the term they used). where the eyeball fails to grow as the child grows. (There is a condition known as Microthalmia, but I don't recall that term being used.) The result is extreme, but at least partially correctable, Hyperopia. There was some speculation that there was a specific Eyeball Growth Hormone, produced by the Retina, that was not being produced properly. I don't know if any further research was done because I have not seen any more information about it. I did a quick Goole search on Nanothalmia that yielded no useful results. I don't think the article was my imagination.

Many years ago, some researchers did some research on baby chicks. They fitted them with minus glasses when they were just days after hatching. The chicks grew up to be very myopic and required glasses to be able to see distance. Do chick eyeballs develop in ways similar to human eyeballs?

I don't know if there would be anything to gain from studying your family's genes, such a study is far beyond my ability, but it would be interesting to learn if many years of close work affected your other siblings vision. If it did not, that tends to beg the question, Why not?

BTW, if you would like to contact me privately, please use cactusjack1928@hotmail.com.

C.


H 07 Aug 2016, 14:29

Cactus Jack

Thank you! Yes, we are seven siblings (two sets of twins). By the way I never mentioned my gender, but I am a female, so my identical twin is also a female. I do not know what made you think we are males, but I felt I should correct the misconception

I guess I should be flattered that you think it would be interesting to study (on) my family. We are nothing special. Out of curiosity, what is it about my family that sparked an interest?

The bit about the eyeball growth hormone is very interesting. Where did you hear or read that from?


Cactus Jack 06 Aug 2016, 21:30

H,

Wow! Quite an accomplished family. 7 siblings, if I count correctly, all highly qualified professionals with advanced degrees.

It would be very interesting to explore the visual history of your grandparents, parents, and siblings and perhaps even do some genetic studies. I don't know about your other siblings, but you and your twin brother inherited some exceptionally good genes to have been able to survive many years of intense study without becoming at least slightly myopic. Many professions are very hard on ones eyesight.

Some years ago there was some research done at Johns Hopkins on Nanothalmia where the eyeball does not develop and grow. There was a hint of an Eyeball Growth Hormone thought to be produced by the Retina, but it was not isolated or identified.

It is possible that the brothers you previously mentioned decided to get some reading glasses simply because they made extended close work, more comfortable. Unfortunately, there is a potential price to pay for that comfort, weakened Ciliary Muscles and early need for close focusing help. However, there is a limit to how much help you will ultimately need. It is simply related to focus distance by Sir Isaac Newton's most fundamental optics formula.

C.


H 06 Aug 2016, 19:29

Cactus Jack

My older brother is a neurosurgeon, older sister is an entrepreneur, my twin is an internal medicine doctor, my younger sister is a mechanical engineer, my youngest sister is a biomedical engineer/ pediatrician, and younger brother is an architect and owns a real estate company.


Cactus Jack 06 Aug 2016, 18:24

H,

You might consider a search on Amplitude of Accommodation.

C.


Cactus Jack 06 Aug 2016, 18:23

H,

That is excellent amplitude of accommodation for a 42 year old. However, that will change with time. There are several equations for calculating amplitude of Accommodation based on age.

May I ask your siblings occupation?

As a person gets older, it is almost universal that the Crystalline Lenses will become stiffer and harder for the Ciliary Muscles to squeeze to increase their optical power. That can take extra effort by the Ciliary Muscles. If the Ciliary Muscles are able to increase the Crystalline Lenses PLUS power to focus close, the stiffness makes them slow to relax. While they are relaxing, a person whose eyes require no correction for distance (Emmetropia) experience the symptoms of Myopia.

You might ask your siblings what prompted them to start using reading glasses so you will know what to expect.

As an Endocrinologist, I am sure you have experience with denial of serious medical conditions. While Presbyopia is not nearly as serious as Endocrinological conditions. It happens to almost everyone by the time they get to 45 or 50, with very few exceptions. Enjoy your Emmetropia as long and you can, but you can be pretty well assured that it will not last forever.

C.


Maurice 06 Aug 2016, 10:01

H, let us know when you get your glasses.


H 04 Aug 2016, 23:37

Cactus Jack

I am an Endocrinologist, and I have an identical twin. For your test, I was able to bring the paper all the way to my nose.


Cactus Jack 04 Aug 2016, 17:43

H,

Unless you are one in a million (or more), it is very likely that you will ultimately need close focusing help. Vision training will not slow the progression of Presbyopia, but it might help keep your Ciliary Muscles in condition.

To some extent, your visual environment can affect how rapidly Presbyopia develops. May I ask your occupation? Also, is your twin Identical or fraternal.

About every 10 to 15 years, the Bates Method or other "methods" will re-appear. The most recent one I remember was the "See Clearly Method" which was advertised extensively, but was ultimately found to be ineffective except in one regard. It significantly improved the wealth of the sponsors.

As a quick test, starting at about arms length, move a book or news paper slowly toward your eyes, until the text just begins to get fuzzy. Measure the distance where that occurs and let me know.

C.


H 04 Aug 2016, 14:01

Maurice,

The last time was almost two years ago. I last had them checked labor day weekend in 2014. I remember tha because I got them checked with the kids (it was their first time).


Maurice 04 Aug 2016, 12:45

H, when was the last time you had your eyes checked? Age 42----it might be a good idea.


H 04 Aug 2016, 11:55

Cactus Jack

I never said anything to any of my siblings. I kept it to myself. So I will not be eating crow. I mention my siblings here to make a point that my blood relatives (even twin) are facing these problems, so is there any hope for me to not have these problems?


Cactus Jack 04 Aug 2016, 08:45

H,

Be really careful about bragging to your siblings about your not needing reading help, unless you really like to "eat crow". You might enjoy reading "Macrae's Story on the Vision and Spex, Fantasy and True Stories thread. It is a true, humorous, "saga" about Macrae's adventures with finally getting glasses and his attempts to hide his vision problems from his siblings. I can assure yo that your time will come and no matter how you cook it, crow is still crow. I have no personal knowledge about eating actual crow, but I understand it it not very tasty. Eating one's words is not much fun either, unless you can laugh about the need to do so.

There are two factors involved in needing close focusing help; Presbyopia and Ciliary Muscle strength (conditioning). There os nothing you can do about Presbyopia, which is the slow, gradual stiffening of the protein that makes up the Crystalline Lens. The gradual stiffening actually starts in childhood, but generally done not become a problem until the late 30s or early 40s, but that is not a hard and fast rule. When the Crystalline Lenses get too stiff for the Ciliary Muscles to be able to nearly instantly change power, there are two visual effect, difficulty in focusing close (arms get too short) and once focused close slow relaxation for distance vision (temporary, blurry distance vision)

The Ciliary Muscles are the tiny muscles that squeeze the Crystalline Lenses to increase their PLUS power to focus close. For their size, they are the strongest muscles in the body, but like all muscles, if you don't use them, they become weak. When you finally get to the point where you need reading help, your Ciliary Muscles will have to work less and will become weaker fairly quickly. It is somewhat like a slow motion cascade of needing more and more external PLUS help. However, fortunately there is an endpoint to this cascade and a limit to how much PLUS focusing help you will need. It strictly depends on how close you need/like to focus. Typical reading distances require +2.50 to +3.00 as dictated by the laws of optical physics.

BTW, don't think for an instant that other people won't notice that you are having trouble focusing close. That just doesn't work, particularly with your family.

C.


H 03 Aug 2016, 21:16

Hi, I just had my 42nd birthday last week, and my twin and younger brother showed with readers. This leaves me as the only sibling without glasses. I am just wondering if there is anything I can do to keep my vision (especially my near vision, all my siblings need reading help now) the way it is, or at least postpone the deterioration?


Cactus jack 19 Jul 2016, 12:35

Taylor,

NJ is right. I am also not an Eye Care Professional (ECP) and don't pretend to be. Hopefully, you are under the are of an ECP that specialized is High and Progressive Myopia. Usually, there is a genetic factor in high myopia, which is why I asked about that. Sometimes it skips generations.

There is a theory that there is a specific Eyeball Growth Hormone that can cause eyeball growth. It has never been isolated and identified.

You probably have not yet studied this in school, but there are three possible causes of myopia, which is an optical mismatch between the total PLUS power of your eye's lens system and the length of your eyeball.

True or Axial Myopia has two causes:

1. The most common is excessive eyeball growth (length)

2. Rarely, it is caused by too much PLUS in your eye's lens system

Pseudo or False Myopia is caused by the Ciliary Muscles and Crystalline Lenses, which is extremely rare in very young people.

If your myopia is caused by excessive eyeball growth, retinal detachment is a risk. If it is caused by too much PLUS in your eye's lens system retinal detachment risk is much lower..

Many ophthalmologists, particularly those who do Cataract Surgery, have an ultra sound instrument which can make painless dimensional measurements of your eyes.

If you would like to learn more about how your eyes work, here is a link. It is an advanced article, but give it a try,

http://www.lhup.edu/~dsimanek/scenario/labman3/eye.htm

C.


NJ 19 Jul 2016, 10:39

Taylor, pleased be advised that no one here is an eye care professional. If you have questions, you should really ask you eye doc.

There have been some studies that suggest bifocals can reduce the progression of myopia, but only modestly. The idea is that providing a reading segment in the lower part of your lenses will reduce the amount by which you need to force your eyes to focus on near objects, perhaps limiting the increase in myopia. To my knowledge, there is no way to actually reduce myopia other than various kinds of refractive surgeries. However, if the myopia is cased by an increase in eyeball length, this won't help lower the risk of retinal detachment.

Again, you should ask your eye doc about these issues.

Best wishes!


Taylor 19 Jul 2016, 09:51

My current prescription is -13.25, -13.50 eith -2.75 and -2.50 astigmatism. I got glasses when I was 3 years old, I never wore them until 7, and started wearing them all the time by 8. If I remember correctly, I got astigmatism when I was 6. Every year (or 6 months) since I got glasses my prescription has increased. Both my parents are farsighted. One of my sisters is nearsighted. I think I have one maybe two nearsighted cousins other than them (and me) my family memebers have perfect vision.I am a girl and I play soccer, and softball.


Cactus Jack 19 Jul 2016, 09:15

Taylor,

Can you provide your complete current prescription and a bit of your visual history. That would help understand your situation.

A few questions.

Myopia typically has a strong genetic component.

1. Are any of your close relatives, also myopic? )parents and grandparents in particular)

2, May I ask your gender and if you play contact sports?

3. May I also ask where you live (country)?

Retinal Detachment is a risk with very high myopia, but there can be other factors. Many people with high myopia never have any problems with retinal detachment and retinal detachment can occur in a person without any myopia. Often retinal detachment, occurs as the result of a blow to the head, if the attachment is weak.

It is very scary if it occurs, but these days the "surgery" is done with a Laser to re-attach the retina to the back of your eyeball.

C.


Taylor 19 Jul 2016, 06:20

Oh, I am 14 years old; and only asked because I was hoping to reverse at least some of my myopia. Yes, I will admit it is partly because my lenses are so thick and my eyes look so weird behind the thick lenses, but for the most part I am really worried about my eye health and sight. I have read from multiple sources that higher levels of myopia is bad for the eye, like it can cause retinal detachment, which requires surgery to fix. I do not want that to happen. I thought if I could reverse some of the myopia, maybe I could save myself from eye problems.


Cactus Jack 18 Jul 2016, 22:33

Anon,

It depends on what type of Myopia you have. You cannot reverse Axial or True Myopia because it is caused by an optical mismatch between the total PLUS refractive power of your eye's lens system and the length of your eyeball. For it to work, you eyeball would have to un-grow.

You might be able to reverse some small bit of Pseudo or False Myopia by wearing PLUS glasses, but it depends on several factors, your age, the amount of Pseudo Myopia you have, and your visual environment. Just to mention a few. Wearing un-needed PLUS glasses can cause problems of their own such as even more blurry distance vision, early onset of Presbyopia.

Every few years there are books and various "methods" promoted to "improve" vision. The Bates Method and the See Clearly Method come immediately to mind. In general they don't work. The only thing they improve is the bank account of the promoter snd decrease the size of yours.

May I ask your age and why you asked?

C.


 18 Jul 2016, 17:38

Is it true that wearing pkaus glasses can reverse myopia?


Cactus jack 06 Dec 2013, 07:08

Astra,

At 24, I think you probably have a long way to go, before you need reading help, but genetics seems to play a big role in when the crystalline lenses become too stiff for the ciliary muscles to be able to control their PLUS power. However, the ciliary muscles are another story. Their strength and conditioning depend on how much exercise they get. Normally, that is not a problem, because they normally get more exercise that any other muscles in the body just doing their job.

Anything that reduces the amount of exercise they get, will affect their conditioning, but the most obvious thing is wearing a reduced MINUS (or increased PLUS) prescription for reading. Full correction of higher MINUS prescriptions may help keep the eye's focusing system in good condition, but even that may ultimately fail. Curiously, there is some evidence that wearing MINUS over correction may help train the ciliary muscles just as weight lifting trains and builds the strength of the arm and leg muscles.

However, wearing MINUS overcorrection may not be a good idea if our theories about the things that stimulate eyeball growth and the genetic propensity for myopia are correct. The wider Depth of Field of MINUS glasses may help a little with focusing close while the minimization of image size on the retina makes reading small text more difficult. It might be possible to reduce the minimization effects of MiNUS lenses by reducing the vertex distance of the corrective lenses to near zero with contact lenses or perhaps even less than zero with internal "contact lenses". Hopefully, by the time you are approaching the age where close focusing help is needed, there will be other solutions for presbyopia.

Wouldn't it be great if you could take an inexpensive pill that would keep the crystalline lenses from aging or perhaps a vaccine given in childhood that would prevent it for a lifetime.

C.


Astra 06 Dec 2013, 01:11

Is it possible to train the ciliary muscles to delay presbyopia onset ?

My age 24.


laulau_fre 05 Dec 2013, 00:40

cactus jack

Thank you very much I understand.

Everyone always had with my correction -7 -8.

So my only alternative will be to wear contact lenses. GOC.

Or to have surgery to be more myopic if with a lot of luck.

I find a doctor who will agree to make me more myopic.


laulau_fre 05 Dec 2013, 00:39

Cactus jack

Merci beaucoup j'ai bien compris.

Tout le monde ma toujours connu avec une correction de -7 -8.

Donc ma seule alternative sera soit de porter des lentilles de contact. GOC.

Ou de me faire opérer pour être plus myope si avec énormément de chance.

Je trouverai un médecin qui accepterai de me rendre plus myope.


Cactus Jack 05 Dec 2013, 00:18

laulau_fre,

Please let me know if the translation is OK.


Cactus Jack 05 Dec 2013, 00:16

laulau_fre,

It is not correct that presbyopia will not affect you because you are nearsighted.

Think of your actual -3.50 myopia as having built in +3.50 reading glasses.

Presbyopia is caused by the crystalline lens becoming so stiff that the ciliary muscles can no longer increase its plus power and it is beginning to happen.

When you were a child, your crystalline lenses had the consistency of gelatine dessert and you likely had about 18 diopters of accommodation range. As you got older, your accommodation range gradually decreased and it is now about 5.50 diopters. When you wear the -7 glasses, you are using +3.50 diopters of your accommodation to focus distant images which leaves only about +2.00 diopters for focusing close. Typical reading distance is 40 cm which requires +2.50 diopters to focus, but your crystalline lenses and ciliary muscles can no longer supply +2.50, only +2.00 and the small print is blurry.

In a few years, presbyopia wil make it impossible for your ciliary muscles and crystalline lenses to compensate for the -7.00 glasses and distant things will be very blurry as if you were wearing -11 or -12 glasses.

English to French translation using Google Translator

Il n'est pas exact que la presbytie ne sera pas pour vous, car vous êtes myope .

Pensez à votre myopie de -3,50 réelle ayant construit dans les 3,50 lunettes de lecture .

La presbytie est causée par le cristallin devient si raide que les muscles ciliaires ne peuvent plus augmenter sa puissance de plus et il commence à se produire.

Lorsque vous étiez enfant , vos lentilles cristallines eu la consistance de gélatine dessert et vous avez probablement eu environ 18 dioptries de gamme d'hébergement. Comme vous avez plus , votre gamme de logements a diminué graduellement et il est maintenant d'environ 5,50 dioptries . Quand vous portez les lunettes -7 , vous utilisez 3,50 dioptries de votre hébergement se concentrer images lointaines qui laisse seulement environ 2,00 dioptries pour la focalisation étroite . Distance de lecture typique est de 40 cm, ce qui nécessite 2,50 dioptries à se concentrer , mais vos lentilles cristallines et des muscles ciliaires ne peut plus fournir 2,50 , 2,00 et que la petite impression est floue .

En quelques années , la presbytie wil font qu'il est impossible pour vos muscles ciliaires et le cristallin pour compenser les verres et -7,00 choses lointaines sera très floue comme si vous portiez -11 ou -12 lunettes aujourd'hui


laulau_fre 04 Dec 2013, 23:17

Cactus jack

Mon anglais est pas très bon. J'utilise un logiciel de traduction. c'est pas évident de ce comprendre.

Je porte une surcorrection depuis mes 24 an. A 24 an je porter du -8 sans compter mon asitgmatisme.

J'ai réduis un peu la surcorrection du à mes difficulté à lire des très petit caractères de près.

J'ai effectivement -3.50 de myopie axile, test sous atropine.

Si je comprend bien à 45 ans comme je suis myope je ne serai pas touché par la presbytie.

Si j'enlève mes lunettes pour lire.

Mais ce que je veux savoir c'est si ma vision de loin sera flou en continuant à porter -7 ?

Je connais goc et je le pratique de temps en temps avec succès, mais je supporte pas je préfére porter mes lunettes -7 tout les jours sans lentilles de contact.


Cactus Jack 04 Dec 2013, 18:20

laulau_fre,

I am not sure you understand how the optical system of the eye, works.

If you actually have -3.50 and -3.25 Axial or True Myopia, it is highly unlikely that you will ever be farsighted (hyperopia). When you wear -6.75 and -7.00 glasses you are creating about -3.50 of Pseudo or False Myopia by using your ciliary muscles and crystalline lenses to add enough extra plus to compensate. This action is usually called Accommodation.

As you get older, Presbyopia will reduce your ability to add the extra plus to be able to wear the -6.75 and -7.00 glasses for distance and also reduce your ability to add additional plus to be able to focus close. You are already experiencing some difficulty in focusing to read and the amount of plus you ultimately need to be able focus close will increase as Presbyopia makes it more difficult to focus close.

It is likely that by the time you are 45, you will not be able to wear the -6.75 / -7.00 glasses for distance and will need an ADD of around +2.00 to +2.50. However, you will always be able to do GOC. We have several members who are wearing GOC glasses in the -15 to -20 range in their 60s.

C.


laulau_fre 04 Dec 2013, 15:03

Cactus Jack

Thank you cactus jack

But I'd like to know when I have 45 years and I am farsighted, is that I can always wear a correction -7 for my distance vision?

Wearing progressive lenses?

You think 1.25 would no longer sufficient?


Cactus Jack 04 Dec 2013, 12:25

laulau_fre,

Presbyopia is catching up with you so progressives or bifocals will help. Presbyopia is caused by your crystalline lenses gradually becoming stiff with age which reduces you accommodation range. It appears that you are wearing approximately -3.50 diopters of over correction. That uses up about +3.50 of your available accommodation. The amount of additional accommodation you need to focus to read is a function of how closely you like to read. For example to read at 40 cm requires +2.50 of accommodation in addition to the +3.50 you need to compensate for your over correction and you are running out.

I would suggest starting with an Add of +1.50, but expect that to increase faster than you would like.

C.


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