Author Topic: Concerns about hyperopia  (Read 2344 times)

Offline ReubenSchwartzschild

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Concerns about hyperopia
« on: August 17, 2014, 12:40:49 PM »
Hi, I have  a question!
If prolonged near work and wearing minus lenses makes one myopic, then will prolonged far work and wearing plus lenses basically make one hyperopic? Isn't that kind of like trading one condition for the other?
Because if that is the case then it would be a problem. I want to be able to see clear at any distance near or far.

Offline Todd Becker

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Re: Concerns about hyperopia
« Reply #1 on: August 17, 2014, 09:41:39 PM »
Hi, I have  a question!
If prolonged near work and wearing minus lenses makes one myopic, then will prolonged far work and wearing plus lenses basically make one hyperopic? Isn't that kind of like trading one condition for the other?
Because if that is the case then it would be a problem. I want to be able to see clear at any distance near or far.

Hi Reuben,

Someone at the AHS conference asked me essentially the same question.  The answer is: it depends on the flexibility of your crystalline lens.

As background, keep in mind that your range of focus is determined by two factors: the ability of your crystalline lens to change shape (via contraction and relaxation of the ciliary muscles) and the overall axial length of your eye.  Think of the the axial length as the setting the baseline focal length for distance, and the lens as providing the fine focus control that allows you to see close up periodically.

To understand how myopia develops, we should realize that our primate eyes evolved to be used most of the time for distance viewing, and only periodically for close up work.  It is the evolutionary mismatch caused by a radical shift towards close work that has led to "spasm" of the ciliary muscles, causing blur in distance viewing.  This is known as pseudo myopia.  When followed by the prescription of minus lenses as a short term "fix" to restore distance focus, there is a secondary defocus for near viewing that induces axial lengthening and a more sustained type of myopia known as axial myopia.  From that point there is vicious cycle of stronger and stronger minus lenses prescribed that temporarily fixes the distance viewing problem, but induces a new round of near work defocus and further axial lengthening. 

Viewing objects right beyond the far point blur (between what I call D1 and D2) -- with or without plus lenses -- will induce a defocus that induces axial shortening, reversing axial myopia.  If you keep pushing this, you will arrive at emmetropia, or normal eye length.  If you keep pushing further, you can induce axial hyperopia, or far-sightedness, making it difficult to view print or objects up close.

However that pertains only to the axial element of focusing ability.  So long as your lens remains flexible and able to be contracted by the ciliary muscles, you'll be able to achieve close up focus, even with a certain degree of axial hyperopia.   This is why it is important to maintain flexibility of the lens.   As we age, the lens tends to harden, and the ciliary muscles atrophy.  The resulting condition of presbyopia refers to a restricted focal range -- both near and far.  This is why older folks often need correction that allows for both close up reading and distance, such as bifocals.

There are basically two strategies for avoiding this situation.  The first is to maintain good vision hygiene by alternating between close and distance viewing throughout the day using your natural eye.  Use print pushing, with plus lenses as needed, when reading or at the computer.  And build in plenty of breaks with distance viewing and active focus to resolve distant details, throughout the day.   David DeAngelis' book, The Secret of Perfect Vision, has good suggestions for eye exercises that maintain the flexibility of the lens and reduce the risk of ciliary spasm.

The second strategy is to eat an eye-healthy diet.  There is evidence that elevated insulin levels and blood glucose leads to weakening of scleral tissue in the eye and induces glycation that can impair the eye and stiffen the lens.  Keep insulin and glucose levels low by moderating intake of carbohydrates and protein.  Eating a phytonutrient rich diet will also stimulate your endogenous antioxidants, preventing oxidative stress and glycation in the eye.

Todd



Offline FonkStreet

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Re: Concerns about hyperopia
« Reply #2 on: August 18, 2014, 01:15:19 PM »
Hi jimboston, in the study you are talking about, the daily changes in axial length are not enough significant to make a difference in visual acuity.


Offline OtisBrown

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Re: Concerns about hyperopia
« Reply #3 on: August 18, 2014, 03:50:31 PM »
Hi Fonk,

Subject: A slight-change in the RIGHT DIRECTION, simply suggests that you should CONTINUE TO DO WHAT YOU WERE DOING - if a plus lens changed your refractive state in a positive direction.

It is true that a one day "statistical event" does not make a "cure".

But we know that the natural eye "goes down" at a rate of -1/2 diopter per year - for each year you are in a "reading environment". 

It would be reasonable to expect that getting the natural eye to "move positive" would be a very slow process.

The real issue (assuming you have self-checked at 20/60 - and -1.25 diopters) is to convince  yourself with long-term resolve to continue your early success (meaning that you have finally confirmed 20/40, after about six months of wearing a plus for near - for all close work - no exceptions).

Prevention is truly difficult, and can not be prescribed.  It does take a person who can make the above commitment - and very few people have that type of interest or motivation to do both the plus, and monitor their Snellen, and WAIT for results.  An exact knowledge of the facts will help you in that respect.

But its all your responsibility.

I would add that a person who is "down to" -1.5 diotpers - will HAVE NO FEAR OF HYPEROPIA.  Just getting to 0.0 diopters (and therefore 20/20) would take about one year, to get that change.  Further, assuming he does "stick" with the plus, and gets to 0.0 diopters (self-checked), he will QUIT wearing the plus and stay in the so-called normal range.

Hyperopia is generally defined as refractive states greater-than 1.0 diopters.  There is no fear of "becoming hyperopic" once you know how to make this measurement yourself.  A slight positive status is necessary for 20/15 and 20/13.



Hi jimboston, in the study you are talking about, the daily changes in axial length are not enough significant to make a difference in visual acuity.
« Last Edit: August 19, 2014, 03:56:28 AM by OtisBrown »

Offline ReubenSchwartzschild

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Re: Concerns about hyperopia
« Reply #4 on: August 26, 2014, 02:43:48 AM »
Hello, thank you for your informative replies, especially yours,, Mr. Becker. I have found a baseball vision exercise whereby you focus one a near object and quickly shift focus to a far away object, I'm guessing this will help ne preserve my near vision.

Today I have had a breakthrough (from working for three hours straight with the Snellen chart), which is consistent with what you wrote in one of your articles on your website, mr. Becker. After a couple of weeks of pratice with no noticeable results, today my vision has finally reached a new level of clarity and sharpness and it has been like this for hours now whereas any improvement before this used to slip away after a few blinks. I am very excited with this!

Offline NickGrouwen

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Re: Concerns about hyperopia
« Reply #5 on: August 26, 2014, 07:20:36 AM »
He Reuben, mooi man, ik heb zelf nog niet al te veel succes gehad met de snellen kaart, zoals je weet maar ik zal het nog eens proberen ;D

I think indeed our eyes were supposed to be used mostly for distance viewing anyway - with minimal near work here and there. Sadly, in our society it is completely the opposite. Yet it is so easy to turn your eyesight around if people would just keep their distance from the screens. My own focusing ability has greatly improved from being 'stuck' in the beginning, as I've said in a post before.