Heterophoria may trigger a host of vision problems and ailments, such as the following:Eyes rapidly become tired when reading or when working at a computer screen. Seeing becomes a strain, frequently resulting in a burning sensation in the eyes, other forms of eye pain, tension headaches, migraines and tension in the neck muscles. Sensitivity to light – even when weather conditions are cloudy and when driving at night.No previous spectacles used have provided comfort of vision. Heterophoria may trigger or exacerbate the ailments described above. Heterophoria is a form of ametropia, or refractive impairment, rather than any kind of disease. This refractive impairment only occurs in dual-eye vision and is triggered by an imbalance in the motive muscles of both eyes. Heterophoria may be corrected via prescription of spectacles in the same way as visual acuity.

The following provides a more precise description of the ailments which may occur in the event that you are experiencing any of the vision problems stated above.

1. Seeing becomes a strain and the eyes rapidly become tired, such as when reading or working at a computer screen. Typefaces appear unstable, and the letters become blurred or dance across the page or screen. This may lead to increased concentration or learning difficulties in the case of children and sometimes results in conspicuous motoric behaviour and a tendency to become fidgety.
2. You experience a feeling of tiredness or a burning sensation in the eyes after a period of concentrated work at the computer. This may frequently result in eye pain, tension headaches and tension in the neck muscles.
3. Problems in focussing the eyes, particularly when shifting your vision from far to near or vice versa. Your eyes need time to adjust to each new visual impression and you find it difficult to focus on a single point of vision for any considerable time. Double vision may occur in individual cases when the body is in a weakened state.
4. Sensitivity to light, including in cloudy weather conditions, when exposed to neon light or when driving at night. Visual acuity problems at dawn and dusk.
   One eye is less involved in the vision process than the other. This may lead to a deterioration in visual acuity or spatial awareness and may also result in feelings of giddiness.
5. One eye is less involved in the vision process than the other. This may lead to a deterioration in visual acuity or spatial awareness and may also result in feelings of giddiness.
6. Tendency to blink, twitch the eyes or rub the eyes, squeeze one or both eyes shut. Frequently a tendency to hold the head at an angle due to the fact that such a position makes vision seem more comfortable.
7. Vision is variable and depends on how you feel on a certain day. Stress also impacts negatively on quality of vision.
8. Children and young people may typically exhibit many of the following characteristics if affected by heterophoria.

• Concentration problems
• Deficiencies in fine-motor skills (painting, crafts work etc.)
• Disturbed motoric behaviour (fidgety)
• Do not like reading
• Produce irregular handwriting
• Cannot form small letters
• Make a large number of careless mistakes
• Write very slowly
• Are cramped and inhibited when writing and write with considerable pressure
• Need frequent breaks when reading or writing

How can these vision problems and discomforts are caused by straining the eyes be remedied?

The first stage is to correct distance visual acuity for each individual eye. This means that the image generated within the eye must not lie in front of the centre of the retina (causing short-sightedness) or behind the centre of the retina (occasioning long-sightedness). Spectacles which do not correct visual acuity properly may trigger the same symptoms which occur in the case of uncorrected binocular impairment.

This is followed by undertaking an additional measurement to check that both eyes are working together correctly. In order for this to take place, the retinal images in both the right and the left eye must be on the centres of the retina. There must not be any horizontal or vertical shift. Any shift of this nature constitutes heterophoria. Once visual acuity has been remedied, a special measurement procedure involving prism spectacles can be deployed to correct heterophoria.

Heterophoria – the reason for many vision problems and discomforts caused by straining the eyes

Heterophoria is a form of ametropia which occurs in dual-eye vision and is triggered by an imbalance in the motive muscles of both eyes. The result of this is that both eyes are not precisely aligned to the object of focus.

The deviation in the optic axes from the point of the object of focus is minimal and scarcely noticeable. This is not the same as strabismus, or a squint. Such a deviation results in a form of ametropia or refractive impairment known as heterophoria.

The impairments triggered by heterophoria may affect all age groups. The effect in children may be to simulate or exacerbate dyslexia.

Heterophoria may cause all the discomforts caused by straining the eyes described above even if you have good distance vision without spectacles.

If heterophoria were not to be corrected when you are fitted with spectacles in the future, your vision would be precisely the same as it was before correction of heterophoria took place and you would still experience all the vision problems and discomforts caused by straining the eyes from which you previously suffered.

Why are instances of heterophoria not addressed in many cases, even though many people suffer vision problems and discomforts caused by straining the eyes as a result?

1. Correcting heterophoria is much more time consuming and labour intensive than correcting visual acuity.
2. The fact that visual acuity is corrected for each eye separately means that erroneous measurements occur relatively infrequently. In the case of heterophoria, however, both eyes are measured at the same time. If the person conducting the test is not sufficiently experienced or skilled, incorrect measurement results may occur much more rapidly. If measurements are incorrect, the prism spectacles prescribed for the person concerned will be ineffectual or incompatible. For this reason, most people measuring for spectacles are content to conduct visual acuity correction only rather than taking the “risk” of undertaking binocular correction.

Testing for heterophoria

All individual vision problems and ailments are recorded before a test for heterophoria takes place. This is followed by a detailed consultation session, during which I will respond to any questions you may have.

I will be in a position to inform you whether you have a form of heterophoria which requires correction once I have tested your visual acuity and dual-eye vision.

If this is the case, I will undertake a brief measurement to carry out an initial correction of the heterophoria. This will, however, be sufficient to show you what improvement could be made to your vision if a correction is carried out.

Most people notice an immediate and often very clear difference in their vision compared to before. This will give you an idea of whether your heterophoria should be fully tested.

I would like to take this opportunity to address an issue which has often cropped up when dealing with people suffering from heterophoria. In my experience, many people are worried about providing incorrect information when having their eyes checked.

Let me reassure you if you are harbouring similar concerns. It is almost always the fault of the person carrying out the checks rather than your fault if imprecise or incorrect information is provided in eye tests.

Intelligible and precise questioning must take place every time someone receives new glasses. Everyone will then be able to provide clear and correct responses. I view such reliable and clear answers as absolutely essential in order to be able to guarantee the correctness of the prismatic adjustments I make.

As many people are as yet unfamiliar with heterophoria and prism spectacles, I would like to continue by responding to a number of FAQ‘s.

Why is heterophoria largely unknown as a concept?

Most people start by visiting an ophthalmologist if they notice problems with their vision or are experiencing discomfort caused by straining the eyes. The ophthalmologist is usually able to exclude any disease as the cause of such complaints.

If no deficiencies in visual acuity are subsequently identified, most people are told the following. “It’s nothing to do with your eyes, your glasses are all right. (Or you don’t need glasses). We haven’t been able to find any reason for your vision problems and for the discomfort you are experiencing.” Any further medical checks undertaken fail to yield any results because heterophoria is triggered by the failure of the eyes to work together sufficiently well rather than being any kind of disease.

For more information, see at TheFreeDictionary, which deals with the topic of latent strabismus (heterophoria).

Many people who go through such experiences and subsequently discover that prism spectacles offer them complete comfort of vision ask me the following question. “Why wasn’t my doctor able to help me and undertake precisely the same action as you? I explained everything to him or her in the most precise of terms! And if my doctor didn’t carry out these procedures, why wasn’t he or she at least able to point me in the right direction?”

I then always try to reassure people that the main duty of an ophthalmologist is to identify and treat disease, whereas an optician’s task is to check and correct vision impairment.

I work in close conjunction with ophthalmologists, doctors from other specialisms, educational psychologists and occupational therapists. Such cooperation is in the best interests of all those involved. I have been cooperating with eye specialists for many years in order to exclude anatomical reasons for vision problems and discomforts caused by straining the eyes.

Most of the time, the eye muscles are able to compensate for any heterophoria without any problem at all. In about 25 percent of cases, however, uncorrected heterophoria will result in discomfort of vision.

If discomfort caused by straining the eyes affects the general well-being of the person concerned, action will need to be taken to correct the heterophoria. This involves wearing a pair of glasses to correct the heterophoria for most of the time.

Contact lenses or an old pair of spectacles not containing a prismatic effect may continue to be worn whilst a person is engaged in sport or during his or her leisure time.

How long does it take to get used to wearing a pair of prism spectacles?

If the prism spectacles have been correctly measured, it will be only a matter of minutes before you will be able to see without any problem at all, and you will have no desire ever to take the glasses off again. It will not take you any longer to become accustomed to wearing such spectacles than would be the case with any other glasses prescribed. Your eyes simply need time to relax. Your prism spectacles will then provide you with clear and strain-free vision over the course of the following years.

Do prism glasses have thicker lenses?

No. In this regard, there is normally no discernable difference between prism spectacles and ordinary glasses which correct visual acuity. Anyone looking at you will rarely be able to tell whether your glasses have a prismatic effect. Prism glasses can also very often (over 90 percent of the time) be set into your existing spectacle frame, even if such a frame is rimless or has a very thin rim. The remaining ten percent of prism glasses can also be set into thin and light frames provided these frames are carefully selected.

Self-Test

As explained above, vision problems and discomfort occasioned by heterophoria can only occur in dual-eye vision.

If you believe that heterophoria is the cause of the vision problems you are experiencing and if an ophthalmologist has excluded any kind of disease as the reason for your discomfort you can conduct the following test. Cover one of your eyes for several hours and observe if this reduces or even eliminates your vision problems and discomfort. If this is the case, it is highly likely that heterophoria is the cause of your problems and you should have your eyes examined.

You can cover your eye using an eye patch or a piece of paper cut to the right size and stuck to one of the lenses of your spectacles if you are already a spectacles wearer. It does not matter whether you exclude your right or left eye from the vision process.

You can also carry out this test if you already have a pair of prism spectacles but are still suffering from discomfort of vision. If the test yields a positive result, your heterophoria has not yet been properly corrected. In such a case, you should arrange for a further examination to be undertaken.

Warning: this test should only be conducted at home in familiar surroundings and should never be carried out whilst you are driving or undertaking other dangerous activities. The duration of the test should also be limited to a few hours. In no circumstances should the test be used to attempt to achieve a permanent reduction in discomfort.

Who is right in the dispute surrounding prism spectacles?

I often hear that ophthalmic opticians, optometrists and ophthalmologists are supposedly engaged in a major dispute on prism spectacles. I do not believe that any such dispute is relevant. I would never say that I was right and other people were wrong. I leave such verdicts to those who are affected.

If the spectacles prescribed to a person enable him or her to see without discomfort, then these spectacles are right. Everything else is wrong.

Any dispute could be brought to an end if all those involved were more prepared to listen to what sufferers have to say.

How can we tell what are correct prism spectacles and what are incorrect prism spectacles?

Any wearer of prism glasses can easily answer the above question for him or herself. This applies to children and young people in exactly the same way as it does to adults.

If the right prism spectacles are being worn, you or your child will be able to respond yes to the following test criteria at all times.

1. Do the prism spectacles enable you to see in a more focused way than was previously the case?
2. Do you have better spatial vision than before?
3. Have your vision problems or the discomfort caused by straining your eyes been fully resolved or significantly reduced compared to before?
4. Are all improvements permanent?
5. Are other complaints absent?

If you can continue to respond yes to all five points during the course of the next few years, you or your child will feel much better than before and you or the child will very much enjoy wearing the prism spectacles. I guarantee our prism spectacles in this respect.

It goes without saying that the prism spectacle guarantee I provide will also apply in circumstances where you are already in possession of one or more pairs of prism glasses which have not yet offered you complete comfort of vision.

You can use the test criteria stated above to check all new pairs of spectacles, including conventional spectacles which only correct visual acuity. If you have recently had your visual acuity corrected but are still suffering from vision problems and discomfort caused by straining your eyes, you should have your eyes examined to check whether there is any instance of heterophoria.

I would also like to mention the topic of visual training within this context. If your heterophoria has been correctly measured, you will be able to see without discomfort and will not require any visual training.

Visual training may be of some assistance if you are still experiencing vision problems and discomfort caused by straining your eyes despite using prism spectacles. Notwithstanding this, I believe that the full and precise correction of your heterophoria is much the better approach to adopt. This will enable you to see without discomfort and will obviate any need for visual training.

How can prismatic values be maintained at a low and constant level?

By only using prisms to compensate for the proportion of heterophoria which cannot be compensated for by the eyes themselves.

What does this mean? Everyone is easily able to align and move his or her eyes on a horizontal plane. The eyes turn inwards for close-up vision and return to a parallel position for distance vision. The effect of this is that the eye muscles are normally able to correct the horizontal aspect of heterophoria without difficulty.

In many such cases, any correction of heterophoria may either prove to be unnecessary or else will be considerably weaker than the measurement result indicated on the Polatest vision testing instrument produced by the company Zeiss (external or internal prism base).

The eyes are not capable of compensating for a vertical muscular imbalance between both eyes. No one has the ability to see with the centres of both retinas simultaneously by directing his or her right eye slightly downwards and the left eye slightly upwards (or vice versa).

Vertical alignment, or straightening of the eyes, is not something which can be learned, not even at specialist vision therapy schools. Notwithstanding this, small vertical deviations from the centres of both retinas may become extremely noticeable and may trigger the vision problems and discomforts caused by straining the eyes as described above.

Due to the fact that vertically aligned instances of heterophoria are generally far less pronounced than is the case with horizontal instances, much weaker prismatic values are sufficient. My experience has taught me that correcting only the proportion of heterophoria which triggers vision problems and discomfort is one of the most important prerequisites for preventing a rise in prismatic values and achieving freedom from discomfort at the same time.

I have used this correction technique for the past 12 years and have not experienced any case in which prismatic values increased or in which surgery to the eye muscles became necessary.

I would very much like to emphasise this point to those who are still undecided because they fear that wearing prism spectacles may lead to a rise in prismatic values or high prismatic values.

The very opposite is the case with the prismatic corrections which I carry out. I provide an unlimited money back guarantee period to reassure you that this is and will remain so.

Prism treatment for the correction of heterophoria

So-called prism treatment involves correcting binocular impairment (muscular imbalance) as strongly as possible rather than as weakly as possible. Prism treatment involves prescribing those affected with stronger and stronger prism spectacles at relatively short intervals in order to achieve the greatest possible positional error of the eyes.

When this positional error has become so large that it can no longer be corrected using prism lenses (because these lenses would then be too thick and heavy), those affected are advised to subject themselves to eye muscle surgery. I believe such an approach to be fundamentally wrong!

I have been correcting instances of heterophoria for more than thirty years, and I know that only a small part of the muscular imbalance is responsible for triggering vision problems and discomfort rather than the muscular imbalance as a whole.

This small part of the muscular imbalance needs to be precisely corrected, not by too little and in no case by too much. Prismatic correction of the whole of the muscular imbalance, or maximum correction of the instance of heterophoria, brings only drawbacks to vision and does not create any benefits.

Many sufferers of heterophoria who have already undergone prism treatment have come to me via my website over the course of recent years. These people have told me, that the stronger and stronger prism spectacles they have been prescribed have worsened their vision rather than enabling them to see better or in a more relaxed way. This left them feeling insecure and doubting the wisdom of continuing with their prism treatment.

Allow me to reassure you in the following terms if you are suffering similar doubts. Even when prism treatment is at an advanced stage, it is still possible to interrupt it and reduce prismatic values to a minimum.

You will enjoy permanent comfort of vision if only the part of the heterophoria resulting in vision problems and discomfort caused by straining your eyes is corrected. This renders any eye muscle operation unnecessary. My guarantee would also offer unlimited validity in such cases.

It would, of course, be much better not to begin with the construction of a prism base in the first place. I also provide a guarantee for this with the prismatic correction I carry out.

If the advice of your ophthalmologist is important to you

Most ophthalmologists in Germany take a sceptical view of prism spectacles. Nevertheless, they constantly stress in the Internet articles they write that they would not have anything against prism glasses if they genuinely help those affected.

This critical question can only be answered by those affected. The test criteria stated above will assist you in making your decision.

Please feel free to have “my” prism spectacles inspected by your ophthalmologist if the varying views on prism glasses are causing you concern.

If both your assessment and the evaluation of your ophthalmologist turn out to be positive, this will provide you with additional confirmation of the correctness of the prism spectacles.

This confirmation on the part of an ophthalmologist also constitutes part of my guarantee. You also have a right to return the spectacles if such a confirmation is not forthcoming.

Double vision

There may be many causes of double vision. For this reason, extensive medical consultations need to take place in the event of its occurrence in order to exclude or treat any diseases which may be present.

If neither an ophthalmologist nor other specialist doctors can discover any diseases which are triggering double vision, it can mostly be eliminated with spectacles.

The probability in this case is that the motive muscles of the eyes are not in balance. This makes it impossible for the visual impressions of both eyes to be melded together to form a single image. Any muscular imbalance of this nature will have been present before the occurrence of double vision, but could still be corrected. The emergence of double vision may be exacerbated by incorrect remedy of visual acuity.

I have specialised in spectacle prescriptions which enable these dual-eye deficits to be resolved. In the case of double vision, I also only correct the element of the heterophoria for which the person affected cannot compensate him or herself. This permits prismatic values to be reduced to a minimum.

Such an approach has proved itself to be a tried and tested procedure for the correction of diplopia (double vision) for many years.

If double vision is not caused by a disease, I am able to guarantee the person affected that I will be able to provide comfort of vision and resolution of the double vision. I need to look at individual cases before determining whether I can offer an unrestricted or partial guarantee.

Everything possible should also be done to remedy double vision with spectacles if it has been caused by illness or injury and continues to persist despite medical treatment. Spectacles can often help in such cases.

I always work in close conjunction with ophthalmologists when correcting diplopia.

Conclusion

I resolve the vision problems and discomfort caused by straining the eyes which can occur in many people as the result of uncorrected heterophoria. Ailments may include rapid tiredness of the eyes whilst reading, a burning sensation in the eyes, sensitivity to light, tension in the neck muscles and headaches.

Heterophoria is a form of ametropia, or refractive impairment, rather than any kind of disease. This refractive impairment only occurs in dual-eye vision and is triggered by an imbalance in the motive muscles of both eyes. This vision impairment can be corrected via prescription of spectacles in the same way as visual acuity.

The fact that errors may more readily be made when measuring heterophoria means that this is an area in which there are many doubts and objections. Notwithstanding this, any criticism levelled should not be generalised. No pair of prism spectacles is the same as the next!

I provide every person suffering from heterophoria with a guarantee for the correctness and benefits of his or her prism spectacles and a three-year money back guarantee.

You can easily check for yourself whether your prism spectacles are correct.

You or your child will enjoy immediate and permanent comfort of vision if your prism spectacles have been measured correctly. I guarantee my prism glasses and offer a three-year money-back guarantee. For this reason, I would like to take this opportunity to restate the five test criteria which you can use to check every pair of prism spectacles.

How can we tell what are correct prism spectacles and what are incorrect prism spectacles?

Any wearer of prism glasses can easily answer the above question for him or herself. This applies to children and young people in exactly the same way as it does to adults.

If the right prism spectacles are being worn, you or your child will be able to respond yes to the following test criteria at all time.

1. Do the prism spectacles enable you to see in a more focused way than was previously
   the case?
2. Do you have better spatial vision than before?
3. Have your vision problems or the discomfort caused by straining your eyes been fully resolved or significantly reduced compared to before?
4. Are all improvements permanent?
5. Are other complaints absent?

If you can continue to respond yes to all five points during the course of the next few years, you or your child will feel much better than before and you or the child will very much enjoy wearing the prism spectacles. I guarantee our prism spectacles in this respect.

It goes without saying that the prism spectacle guarantee I provide will also apply in circumstances where you are already in possession of one or more pairs of prism glasses which have not yet offered you complete comfort of vision.

As a result of this guarantee and mouth-to-mouth propaganda, I now deal virtually exclusively with glasses prescriptions involving the resolution of vision problems and discomfort caused by straining the eyes. Most of my clients have undertaken several unsuccessful attempts to regain comfort of vision in the past. Quite a lot of them have felt that they are a problem or individual case. These feelings have sometimes brought mental strains in their wake.

Once their heterophoria had been measured, many of those affected were correspondingly even more surprised at how comparatively easily their problems could be resolved.

From my point of view, the money-back guarantee has proved to be very effective. It creates trust and also acts as the very best instrument which those affected can use to check the quality of the treatment they have received. This is why many people who were previously unsure have decided to have their heterophoria measured and a pair of prism spectacles prepared.

I would like to take this opportunity to point out that I underwent a learning process extending over many years before being able to measure binocular impairments in such a way so as to be able to guarantee vision without discomfort. The experiences of those who have suffered from binocular impairment and the experiences I have been able to glean from such persons have been the key element within this learning process.

Please accord due consideration to the testimonials of those who suffer from binocular impairment and have been wearing prism spectacles for a long period of time. Although these experiences vary greatly, they all have one thing in common. All those affected wish to lend expression to the fact that their prism spectacles have been of considerable assistance to them.

Another thing which emerges from the experiences related, however, is that many people fail to understand why a cooperative approach is not adopted in many areas. For this reason, I would like to conclude by pointing out the following.

Working together to correct instances of heterophoria

I am prepared to take over cases from colleagues, ophthalmologist and other professionals who do not have time to measure instances of heterophoria. The same applies in the case of those affected whose heterophoria is difficult to correct or where the plan is to end treatment even though the respective vision problems and discomfort caused by straining the eyes have not been resolved.

I also provide an unrestricted guarantee and three-year money-back guarantee for my prism spectacles in such cases as described above if the respective vision problems are not resolved and the discomfort caused by straining the eyes cannot be permanently and fully rectified. Both the professional providing initial treatment and the person affected would be in a position to judge this.

I do not require any initial information to take cases on this basis. The pair of spectacles last worn by the person affected is sufficient. Further case management and provision of care for the person affected can then be passed back to the responsibility of the professional providing initial treatment.

Jürgen Peschlow staatl. gepr. Augenoptiker / Optometrist
10711 Berlin
Kurfürstendamm 117