·         Arousal

·         The Brain

·         Exercise

·         Indoor Air Pollution

·         Muscle Tension

·         Nutrition

·         Posture

·         Sensory Processing

·         Sleep

·         Other Suggestions


Research Topics


My Theories

Former Theories



The Cause of Internet and TV Addiction?


Vision Suggestions


·        The Visual Sense

·        Binocular Functions

·        Mobility/Ocular Motility

·        What is Mobility/Ocular Motility?

·       Problems with Mobility/Ocular Motility

·        Improving Mobility/Ocular Motility

·        Eye Movement

·        The Bates Method

Note: The Bates method can be helpful even if you don't wear glasses

·        Computer Programs

·        Computer Vision Syndrome

·        Conjunctivitis (Pink Eye)

·        Dry Eye Syndrome

·        Symptoms, Causes and Treatment

·        More Causes

·        Related Conditions

·        The Most Common Cause

·        Flicker

·        Laterality: Correcting Eye Dominance

·        Nutritional Optometry

·        Vision and Brainwaves

·        Vision Therapy

·       Description

·       3D Stereo Images

·       Treatment Options


The Visual Sense

Reliance on Vision for Proprioception

"Vision exerts strong and sometimes supreme command over our other senses, as optical illusions demonstrate, and it exercises similar effects on our posture and locomotion (movement). With one’s eyes closed, standing soon becomes difficult, and, unless by luck, we would find it impossible to thread a needle."

ILT: Causes


Shortcomings of Vision Exams

Testing Clarity of Vision

"Most people think that if a child’s vision is 20/20 then everything is fine. This is usually tested by a nurse with a Snellen chart (containing letters of different sizes that have to be identified at a certain distance)."

ILT: Causes


Lack of Testing Binocular Coordination, Accommodation, etc.

"What needs to be understood is that vision is more than just clarity. It also includes binocular coordination, speed accommodation, vertical movement and other visual functions necessary to visualise, understand and apply the information that comes through the eyes."

ILT: Causes


Learning Problems and Vision

Children may not have these abilities [e.g. binocular coordination] in spite of having ‘good eyesight’ and this results in learning problems. Difficulties arise because vision impaired children rarely report symptoms. They think everyone sees the same as they do. Our two eyes are supposed to work together - to perform as one entity. This is a skill that must be acquired through use during the preschool years. Not all children adequately develop visual skill and this can interfere with comprehension, the ability to perceive spatial relations, and the ability to concentrate."

ILT: Causes


Misdiagnosis of ADD

"There may be visual discomfort or distortions of the text while reading. This reduces close attention to details and sustained mental effort. As a result, a child will be easily distracted. The signs of inattention are not only observable, but also many times interpreted (or misinterpreted) simply as Attention Deficit Disorder."

ILT: Causes


Mobility/Ocular Motility

What is Mobility/Ocular Motility?

The Oculomotor System

The oculomotor system is the system that controls eye movement. The function of this system is to bring the fovea of the retina (the region where vision is sharpest) into alignment with a visual target of interest and to maintain this alignment. In such a seemingly simple movement such as the control of the eye, there are distinctive movements:

·        rapid search or saccadic eye movements

·        movements governed by the semicircular canals (the vestibulo-ocular reflex)

·        smooth pursuit tracking (ocular motility)

ILT: Causes


Saccadic Eye Movements

"Saccadic eye movements represent a scanning of the field of view - a search for targets. We are constantly shifting our eyes from position to position from one object to another, often without a head movement. There are alternate periods of fixation and shift, fixation and shift, etc. These eye movements are enormously rapid and is the fastest movement the body performs."

 ILT: Causes


Vestibulo-Ocular Reflex

"Vestibulo-ocular reflex is a response that makes it possible to maintain visual fixation on a target no matter how the head is moved. For example, if you are looking at this page and you turn your head, your eyes will turn in the opposite direction so that you do not lose focus. This is made possible by input from the vestibular organ that generates and equal but oppositely directed eye movement that corresponds to the speed of the head movement."

 ILT: Causes


Ocular Motility/Smooth Pursuit Tracking

"Smooth pursuit tracking is known as ocular motility (frequently called visual tracking). This voluntary eye movement is used for tracking an object (a fly or an airplane, for example) as it moves in the visual field. It requires the eyes to move smoothly through all planes of the visual field without blurring or loss of image. This ability is dependent on the muscles and cranial nerves that service the eyes, as well as on the vestibular system which provides information and regulation. It is very important to ease of reading and writing."

ILT: Causes


Problems with Mobility/Ocular Motility

"The following are issues that may occur in a person experiencing difficulties with ocular motility:


∙          Inability to hold head still while tracking


∙          Dizziness and/or nausea when required to track


∙          Pain, watering, discomfort when required to track


∙          Reporting that objects blur or are lost in the field of vision when required to track


∙          Rubbing eyes after use


∙          Frequent headaches after visual work


∙          Frequent stomach aches after visual work


∙          Eyes move with a jerky or bouncy pursuit when tracking


∙          Eyes stop tracking an object that continues to move


∙          Overflow movements to other parts of the face or body when attempting to track


∙          Inability to read aloud, although can grasp meaning from silent reading."

ILT: Causes


Improving Mobility/Ocular Motility

Bates Method: Mobility


Computer Monitor Viewing Distance and Angle

Minimum Viewing Distance

"It is difficult to set an exact limit for a minimum viewing distance. If sustained viewing closer than the resting point of vergence contributes to eyestrain, perhaps we should say that eye-screen distance should not be closer than the resting point of vergence. (On average, about

·        45 inches away at horizontal eye level and

·         35 inches away with a 30-degree downward gaze angle.)

     But there are no cliffs in ergonomics (one inch closer and you fall): If your RPV at a 30-degree downward gaze angle is 35 inches, your eyes are not going to fall out with a viewing distance of 30 inches."

Office Ergonomics Training: Eyestrain and Computer Monitor Viewing Distance


"I recommend at least 25 inches. But closer-viewing distances do not bother some people."

Office Ergonomics Training: Eyestrain and Computer Monitor Viewing Distance


Area of Discomfort

"Somewhere between your resting point of vergence and 6 inches in front of your nose you are going to experience discomfort. That distance is a combination of gaze angle, how long you've been working at the computer, your individual visual system's capabilities, and a number of other factors."

Office Ergonomics Training: Eyestrain and Computer Monitor Viewing Distance


Things to Consider

·        "To allow for greater eye-to-screen distances, we need software programs and monitors that allow font sizes to be increased easily.

·         We need guidelines that don't force people to sit closer to their monitors than the distances at which they are comfortable."

Office Ergonomics Training: Eyestrain and Computer Monitor Viewing Distance


Positioning your monitor at a 30-degree downward gaze angle may lead to bad habits such as rounded shoulders and forward head posture.


Computer Programs

Break Reminder Programs


· Search results for 'break reminder'


Related Topics

·        Computer Vision Syndrome

·        Light Sensitivity: Functional Photophobia (e.g. cover one eye [preferably the should-be-dominant eye; please see ‘Laterality’ page for additional information] and look into distance for 20 seconds)

·        Vision: Bates Method: Accommodation


Computer Programs for Convergence Insufficiency

·        Vision: Binocular Functions: Convergence Insufficiency: Suggestions: Convergence Exercises (Orthoptics): Computer Programs


Computer Programs for Amblyopia


·        Vision: Binocular Functions: Improving: Amblyopia: Treatment: The NeuroVision Treatment



Computer Vision Syndrome

What is Computer Vision Syndrome?

"Computer vision syndrome (CVS) is a condition that affects many computer users. Approximately 70% of computer workers are reported to having vision problems. About Vision Problems



"The symptoms CVS include

·        eyestrain,

·        dry or burning eyes,

·        blurred vision,

·        headaches,

·        double vision,

·        distorted color vision, and

·        neck and backaches." About Vision Problems


Risk Factors

·        The condition is caused by various factors. One factor is poor visual skills such as accommodative (eye focusing) skills or binocularity (eye coordination/eye teaming [convergence]) skills.

·        Another factor is the tendency of computer users to stare at monitors for long periods without changing eye focus [accommodation] from time to time.

·        The distance between a computer user and amonitor[viewing distance]is another factor.

·        Room lighting,

·        monitor glare,

·        screen color,

·        print color, and

·        print size

can also be contributing factors to this condition." About Vision Problems


Vision Therapy vs. Glasses

"Glasses, contacts or surgery can not correct all of the visual symptoms of CVS. Non-surgical relief can be obtained through vision therapy. Vision therapy helps relieve underlying eye muscle disorders, which cause most of the symptoms of computer vision syndrome."

Technology: Computer Vision Syndrome Growing Concern



·        How can you care for your eyes when using a computer?


Conjunctivitis (Pink Eye)

What is Conjunctivitis?

"Conjunctivitis is one of the most common and treatable eye conditions in children and adults. Often called "pink eye," it is an inflammation of the conjunctiva, the tissue that lines the inside of the eyelid and helps keep the eyelid and eyeball moist."

WebMD: Allergic Conjunctivitis



·         "Redness, irritation, itchiness; may produce lots of tears

·         Clear or yellow discharge that may make the eyelids stick together, especially in the morning

·         Swelling of eyelids"

Conjunctivitis Fact Sheet


"Symptoms suggesting a more severe eye infection include:

·         Severe eye pain

·         Change in vision

·         Extreme sensitivity to light

·         Marked heat & swelling of eyelids"

Conjunctivitis Fact Sheet



·        "Viruses,

·        bacteria,

·        irritating substances (shampoo, dirt, smoke, pool chlorine),

·        sexually transmitted diseases (STDs), or

·        allergens (substances that cause allergies)

can all cause conjunctivitis. Pink eye caused by bacteria, viruses, or STDs can spread easily from person to person but is not a serious health risk if diagnosed promptly; allergic conjunctivitis is not contagious."

WebMD: Allergic Conjunctivitis



·         "Don't touch or rub the affected eye(s).

·         Wash your hands often with soap and warm water.

·         Wash your bed linens, pillowcases, and towels in hot water and detergent to reduce allergens.

·         Avoid wearing eye makeup. Don't share eye makeup with anyone else.

·         Never wear another person's contact lens. Wear glasses instead of contact lenses to reduce irritation.

·         Wash your hands after applying the eye drops or ointment to your eye or your child's eye. Do not use eye drops that were used in an infected eye in a non-infected eye."

WebMD: Allergic Conjunctivitis


Dry Eye Syndrome

Symptoms, Causes and Treatment

"Coping with computers and their tiring (read: drying) effect on the eyes is an ever increasing problem.  The problem is caused by staring in one direction for long periods.  This reduces the blinking frequency and increases evaporation time.  Develop the habit of frequently looking away. Every time you change your direction of gaze, you blink your eyes."

eyenet: Dry Eye Syndrome


More Causes

"First, however, it is crucial to determine why the condition exists, and to evaluate whether the symptoms reflect a more serious health problem. Untreated, a dry mouth can lead to sores, infections, and tooth decay. If dry eyes are left untreated, damage to the cornea (the clear front part of the eye) could result, possibly threatening vision."

When Eyes Turn Desert Dry


Related Conditions

"Blinking serves to spread tears across the eye's surface but also to drain the tears from your eye. When you blink tears are moved towards your nose by the eyelids and down the tear drainage ducts. If the tear drainage system is overactive then it may cause Dry Eye as well as congestion of the nose, sinus and throat."

Preventive Medicine: Dry Eye Syndrome


·        "Sinus congestion

·        Nasal congestion

·        Runny nose

·        Postnasal drip

·        Chronic cough

·        Bronchitis

·        Allergies or hay fever

·        Frequent colds

·        Middle ear congestion

·        Dry throat or mouth

·        Headaches

·        Asthma"

Preventive Medicine: Dry Eye Syndrome


"Among those who suffer from Dry Eye Syndrome and related tearing disorders, nearly half also experience related symptoms involving the nose, throat, and sinus.

These include:

  • Nasal or sinus congestion, post nasal drip, and sneezing.
  • Allergy and hay fever symptoms.
  • Middle ear congestion.
  • Chronic coughing.
  • Headaches."


Ear Congestion


The Most Common Cause

"Insufficient production of the aqueous component of the tear film is the most common cause of dry eye. The resulting condition, known as keratoconjunctivitis sicca (KCS), is usually due to decreased tear production by the accessory lacrimal glands. Inflammation of the lacrimal glands, a common cause of dry eye, may also be accompanied by inflammation and drying of other mucous membranes, particularly those in the mouth, vagina, and/or respiratory tract."

Alcon: Dry Eye Syndrome


Eye Movement

·        Choose the right font to reduce eyestrain



Things to Consider

LCD and Flat-Screen CRT Monitors

Some people don't think LCD monitors flicker at all, but some of them do flicker. There are also flat screen CRT (Cathode Ray Tube) monitors. Some of these new CRT monitors advertise that they have higher refresh rates. A higher refresh rate will reduce flicker. However, some companies carelessly advertise that certain monitors that are known to flicker have "absolutely no flicker".


According to LCD flicker is "undetectable to the human eye and does not cause eyestrain". However, flicker can be exacerbated by decreasing the refresh rate and the room lighting, or by increasing the resolution, the number of colors, or the brightness. Some people are also more sensitive to flicker than others.

Dream Screens



Minimizing Flicker

If you can't or aren't willing to avoid computer monitors, and other devices that flicker such as fluorescent lighting, you can reduce eyestrain by reducing flicker as much as possible. There are many web pages with advice on how to reduce flicker such as:

Minimizing Flicker


Refresh Rate

Refresh Rate: What is a Refresh Rate?

The refresh rate is the number of times a monitor's screen is displayed per second. Maximizing your monitor's refresh rate will reduce flicker. Flicker can also be made worse by increasing the brightness, the resolution and the number of colors of your display. If the resolution and the number of colors are increased, it takes longer for your computer's screen to be redrawn. This decreases the refresh rate.


Refresh Rate: Computer Games

There are also some computer games which may change the refresh rate of your monitor to increase performance. In order to maximize the refresh rate it's a good idea to make sure you have chosen the lowest resolution the game will allow.


Fluorescent Light Sensitivity

"Florescent lights bother some people because they 'flicker' at a high frequency.

·        It might be worth taking a very bright light to work and just putting it on your desk. This might be helpful in 'blocking' the effect of light input of fluorescent by an incandescent light.

·        Is it possible to just disconnect the bulbs directly above your desk and use a floor or desk lamp to illuminate your cubicle?"

MDA: Fluorescent Light Sensitivity


3D Stereo Images

Things to Avoid

"A few people do feel uncomfortable sensations in their eyes, but I would compare those sensations to the aches that come from exercising an out-of-shape muscle in your body. It's important not to strain or push too hard. I wouldn't 'go for the burn' with your eye muscles! In How to See 3D we emphasize remembering to breathe, relax, blink and smile." Exercise for the Eyes



"3D stereo images [e.g. stereograms] are powerful tools for training the two eyes to work together as a effective binocular team. Stereo viewing is particularly useful in treating problems with binocular vision or stereo vision such as, amblyopia ('lazy eye') and strabismus ('crossed-eyes' or 'wall-eyes') [stereograms may also be used to treat convergence insufficiency]." Eye Exercises



How to See 3D

·  How to See 3D


Parallel Viewing: Further Instructions

There are some similarities between parallel viewing and the Bates method exercise palming with visualization. In the section Palming: Instructions it is recommended to palm for at least four minutes. It is also recommended to palm three to five times in succession.


Parallel Viewing vs. Cross Viewing

"Parallel-viewing can relax your overworked eye muscles. Alternating between parallel-viewing and cross-viewing can be a callisthenic work-out for the eyes. It can loosen up tight, overstressed eye muscles." Exercise for the Eyes


Cross Viewing is Indispensable

Cross viewing strengthens the eye muscles. Parallel viewing alone will only relax your eyes. Without cross viewing, the ability of the eyes to coordinate their activity will not improve.


Increasing Alpha-Theta Waves/Decreasing Beta Waves

"Notice the moment of slipping into the experience of three dimensional space. The brain seems to have locked onto the super-imposition of the two images, and at that very moment a brain-wave shift can be noticed. Alpha brain waves have increased. This can be experienced as a feeling of letting go, a sigh, a deepening relaxation. Apparently, visually harmonizing the two halves of the brain in this unusual way promotes an increase in alpha waves[probably alpha-theta waves (alpha-theta waves are a subset of alpha waves with a frequency of 7-8 Hz). Brain wave measurements were taken with an analyzer from IBVA Technologies, Inc."

Free Viewing Stereo Images


More information about alpha-theta and beta waves can be found on the Brainwaves page.



The palming exercise may be helpful in resting the eyes before or after viewing stereo images.


3D Stereo Images vs. Sunning Exercise

Using either 3D stereo images or Bates' sunning exercise may be helpful for treating light sensitivity. However, one advantage of the sunning exercise is that the head is moved during this exercise. Head movement stimulates the inner ear and may improve the vestibular system and proprioception.

·        Neurodevelopmental Delays: Improving the Vestibular System

·        Neurodevelopmental Delays: Improving Proprioception



One advantage of stereo viewing is that it can be an indicator of the quality of your binocular vision. If you have a hard time seeing stereo images then your binocular vision may need improvement. You may need to rest your eyes by 'palming', or you may need to do some breathing and blinking exercises.

     It's a good idea to check your binocular vision on a regular basis.



The eye accommodates as it changes focus for far and near objects. Since most people always view stereo images from the same distance, stereo images aren't very helpful for treating accommodative insufficiency.


Vision and Brainwaves

Convergence, Divergence: Alpha-Theta

·          Vision: Bates Method: Accommodation: Convergence, Divergence

·          Brainwaves: Alpha-Theta Brainwaves


Problems with Vision: Too Much Beta

·          Vision: Binocular Functions: Amblyopia: What is Amblyopia?

·          Vision: Binocular Functions: Convergence Insufficiency: Convergence Insufficiency and ADHD

·          Reseach Topics: Similarities with ADD: Symptoms: Attention

·          Research Topics: Brainwaves: Beta Brainwaves

·          Research Topics: Brainwaves: Beta Brainwaves: Too Much Beta


Synchronous Alpha

·           Research Topics: Brainwaves: Alpha Brainwaves: Synchronous Alpha


Immobility and Flexibility

·          Reseach Topics: Brainwaves: SMR or Low Beta Brainwaves: Immobility

·           Reseach Topics: Brainwaves: Brainwave Therapy: Flexibility: Moving between States

·           Vision: Binocular Functions: Accommodative Insufficiency


Vision Therapy

Note: More information about vision may also be found in other sections such as ‘Convergence Insufficiency’ (in the ‘Binocular Functions’ section) or the ‘Bates Method’ page.


·           AOA Position Statement on Optometric Vision Therapy

·           Vision Therapy FAQ


3D Stereo Images

·          Vision: 3D Stereo Images


Treatment Options

Note: Vision software is commonly referred to as ‘vision therapy software’ or ‘orthoptic software’.

·          Indiana University: Virtual Classroom: Photo Index

·          Indiana University: Virtual Classroom: Sequential Treatment Approach

·          Yahoo: Vision Software

· Vision Therapy (sponsored links)

·          EyeWorks - The First Vision Therapy Software Designed For Every Computer User. Version 1.0 (£16.50 UK)

·          VisionLAB : A Multimedia Visual Experience - Windows (£55.00 UK)

·          TopVision Personal ($99 USD)

·           TopVision Professional 2.0 ($199 USD)



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