·         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?


Light Sensitivity


·        Causes

·        Treatment

·        Suggestions

·        Anti-Glare Screens

·        Changing Background Colors

·         Contrast and Brightness

·         Customize Your Mouse Pointer

·        Functional Photophobia, Covering One Eye

·        Lighting

·        Movie Theaters

·        Sensory Processing

·        Sjögren’s Syndrome

·        Sunglasses

·        Sunlight

·        The 'Sunning' Exercise

·        Tinted Glasses

·           Description

·          Effects

·          UV-Blocking Lenses

·          Blue-Blocking Lenses

·          Things to Consider

·          Products

·           Reviews

·           Things to Avoid

·         Related Topics




“Photophobia or light sensitivity is a common eye complaint. It can result from several different conditions and in most cases is easily treatable.”

Eye Care Specialists: When the Light Hurts Your Eyes


Stimulants, Medication, Adrenaline

·        “Certain medications and illegal drugs can cause photophobia by simply dilating the pupil and allowing an excessive amount of light to enter the eye.

·        Frequent use of cocaine [other stimulants, such as adrenaline, can cause the pupils to dilate] can cause a chronic dilation of the pupil.

·        This side effect may lead to the inappropriate use of sunglasses.”

Eye Care Specialists: When the Light Hurts Your Eyes


·        The Brain: Adrenaline


Functional Photophobia

·        Vision: Nutritional Optometry: Functional Photophobia


Inflammation of the Iris (Iritis)

“The most common cause of photophobia is inflammation of the anterior region of the eye, which includes the colored iris.

·        The muscular iris controls pupil size and adjusts the amount of light entering the eye.

·        Just as a sore back hurts when you bend it, an inflamed iris muscle painfully constricts when light hits the eye.

·        Even if the injured eye is patched, the light sensitivity continues because light hitting the uninjured eye causes both pupils to constrict.”

Eye Care Specialists: When the Light Hurts Your Eyes



“Another common cause of photophobia is a cataract. When the natural clear lens of the eye becomes cloudy, a cataract has formed.

·        Cataracts tend to scatter light, similar to a frosted window in wintertime.

·        The disrupted image causes discomfort which is perceived as pain. It is not fully understood why this condition results in discomfort. Possibly, the scattered light may cause a brisk, spastic constriction of the pupil which may contribute to the feeling of discomfort. Most likely the feeling is subjective and develops at a higher, emotional level.

·        Fortunately, symptomatic cataracts can be removed with a very high success rate, eliminating the photophobia.”

Eye Care Specialists: When the Light Hurts Your Eyes


Serotonin Levels

·        The Brain: Serotonin: Serotonin Levels: General Effects


Other Causes

“Occasionally, a patient will complain of light sensitivity, for which no logical explanation can be found. Most of these individuals tend to be fair skinned, with blue eyes. The treatment is the judicious use of tinted glasses to relieve their symptoms.”

Eye Care Specialists: When the Light Hurts Your Eyes


“People with lighter-colored eyes, cataracts, and those who suffer from migraine headaches are more likely to notice sensitivity to light and glare.” Photophobia (Light Sensitivity)


“Often, photophobia is a symptom of another underlying problem, such as a

·        corneal abrasion,

·        uveitis, or

·        A central nervous system disorder such as meningitis.” Photophobia (Light Sensitivity)


“Light sensitivity may also be associated with

·        retinal detachment,

·        Contact lens irritations,

·        Sunburn and

·        refractive surgery.” Photophobia (Light Sensitivity)


“Photophobia often accompanies

·        Albinism,

·        Total color deficiency (seeing only in shades of gray),

·        Botulism,

·        Rabies,

·        Mercury poisoning,

·        conjunctivitis,

·        keratitis and

·        iritis.” Photophobia (Light Sensitivity)


“Some medications may cause light sensitivity as a side effect, including

·        belladonna,

·        furosemide,

·        quinine,

·        tetracycline and

·        doxycycline.” Photophobia (Light Sensitivity)



Underlying Causes

“The best treatment for light sensitivity is to treat the underlying cause. In many cases, once the triggering factor is treated, photophobia disappears.

     If you are taking a medication that causes light sensitivity, talk to the prescribing physician about discontinuing it or replacing it with another drug.” Photophobia (Light Sensitivity)



“If you're sensitive to light, avoid bright sunlight and other bright lights. Wear wide-brimmed hats and sunglasses with ultraviolet (UV) protection.” Photophobia (Light Sensitivity)


Inflammation of the Iris (Iritis)

“The treatment for inflammatory light sensitivity is two fold.

·        First we dilate the inflamed pupil with special medications [there are other, natural, ways of dilating the pupil, such as by preventing light from entering both eyes]. This chemically paralyses the pupil in the open position so it cannot move. Thus, the pain is reduced because iris movement is minimized.

·        Second, we treat the eye with steroid drops to reduce the inflammation. Significant relief is usually felt within twelve hours.”

Eye Care Specialists: When the Light Hurts Your Eyes


Steroid drops are given to reduce inflammation. Drops will be used to dilate the pupil both to relieve discomfort and prevent adherence of the iris to the lens.

     Most cases of iritis respond to drops alone. A minority of patients require additional injections of steroid around the outside of the eye or a course of oral steroids.” Disorders: Iritis




Anti-Glare Screens

If you're eyes become tired from overexposure to bright light you might want to buy an anti-glare screen, which you can attach to your computer monitor.  


Screen Filters

·        Indoor Air Pollution: Electromagnetic Waves: Avoiding EMFs


Changing Background Colors

Note: Please read the section ‘Contrast and Brightness’ below before reading this section.

Eyestrain and flicker might also be reduced by changing the background colors of your computer applications from the color white, to a darker color, and making the text brighter if necessary.

Instructions for Changing Background Colors in Microsoft Windows, Internet Explorer and Access


Contrast and Brightness

Note 1: Some displays don’t have a ‘contrast’ control, but instead have a ‘picture’ control. If this is the case, the picture control may be used to adjust the white areas of the picture and the brightness control may be used to adjust the dark areas of the picture.

Contrast vs. Brightness

If you are light sensitive, try setting the brightness and contrast as low as possible. If the lowest settings are too dark [if the screen is too dark it may be difficult to read, and your eyes may become more strained], adjust the contrast before adjusting the brightness.

     Adjusting the contrast is preferable to increasing the brightness.  Contrast is the degree of difference between the lightest and darkest parts of a picture.


Adjusting LCD and CRT Monitors

"LCDs do not suffer from any of the CRT afflictions to be discussed in the remainder of this note. For good LCD viewing, set brightness so that whites are displayed at a comfortable intensity. Then, set contrast so that blacks and whites are as distinct as possible - that is, so the displayed contrast ratio is sufficiently high."

Reducing eyestrain from video and computer monitors



In addition to computer monitors, the contrast and brightness of most television sets can also be adjusted. Although, there are some television sets that are very bright, even at their lowest settings.


Room Lighting

Televisions and computer monitors should be about as bright as the room lighting.

If the brightness of a room is affected by daylight, it may be necessary to adjust the contrast or the brightness several times per day.


·        Vision: Bates Method: Accommodation: Changing Focus, Room Lighting


Things to Consider

·        If your monitor is too dark, it may exacerbate eyestrain. But if your monitor is too bright it can aggravate conditions such as light sensitivity.

·        It seems that even minor adjustments in contrast and brightness can have a considerable impact on the amount of light sensitivity you experience.

·        A contrast setting that is too high (commonly referred to as ‘high contrast’) may exacerbate glare sensitivity. A contrast setting that is too low exacerbates eyestrain (e.g. letters are harder to read). If your contrast setting is much higher than your brightness setting you might want to try adjusting your monitor by

  • Lowering your contrast setting until the screen is almost black
  • Increasing your brightness setting to a comfortable level
  • Increasing your contrast setting to a comfortable level
  • If your monitor greatly restricts your ability to lower the contrast, you might want to experiment with programs such as Powerstrip


Customize Your Mouse Pointer

Following a bright white mouse pointer across your screen can easily tire your eyes and lead to problems such as convergence insufficiency. Changing your pointer so that it is black puts less stress on ocular motility/smooth pursuit tracking.

eHow: Computers & Home Electronics Cente: Operating System Basics: 'How to Customize Your Mouse Pointer'


Functional Photophobia, Covering One Eye

·         Vision: Nutritional Optometry: Functional Photophobia

·        Vision: Binocular Functions: Amblyopia

·        Vision: Binocular Functions: Convergence Insufficiency

·        Vision: Bates Method: Palming: Casual Palming



Risk Factors:

·        High intensity light in area with computer use.

·        Insufficient light on paper.

How to Reduce Risks:

·        Reduce light.

·        Add a task light to focus on the document but not the computer monitor.”

DEHS UMN Workstation Ergonomic Checklist


·        Contrast and Brightness: Room Lighting


Movie Theaters

"A lady with compound myopic astigmatism suffered from almost constant headaches which were very much worse when she took her glasses off, The theatre and the movies caused her so much discomfort that she feared to indulge in these recreations. She was told to take off her glasses and advised, among other things, to go to the movies; to look first at the corner of the screen, then off to the dark, then back to the screen a little nearer to the center, and so forth. She did so, and soon became able to look directly at the pictures without discomfort."

Imagination Blindness: The Cure of Imperfect Sight by Treatment without Glasses


"If you are very light sensitive you may want to start [bates' sunning exercise] by closing your eyes and just facing into the sky but not directly at the sun. Note: At no time are you to open your eyes while looking at the sun!! This stimulates the rods and cones in your eye. Anytime I come out of a very dark place, like a movie theater, I do this exercise for about 20 seconds, and have no problem. I do not wear sunglasses anymore on a regular basis. I keep them handy for glare situations and only then when I'm wearing contact lenses which is not very often anymore"


 Sensory Processing

·        Sensory Processing: Tips


Sjögren’s Syndrome

"According to the NIH, women are nine times more likely to have the disease, which often shows up after age 50…The bottom line is before seeking over-the-counter or prescription solutions your grandmother should check with her doctor."

When Eyes Turn Desert Dry



Advantages and Disadvantages, Alternatives

·        "It goes without saying that, whenever possible, sunglasses are to be avoided.

·        After Bates training you are less likely to feel the need of them anyway, but if you ever do, a wide-brimmed hat or sunshade will probably give all the protection necessary.

·        In temperate latitudes, sunglasses are usually only needed in conditions of exceptional glare (during prolonged exposure to sunlit snow, for example);

·        in the tropics, however, and particularly for Caucasians and others whose forbears evolved in more temperate zones, sunglasses may be required more often.

·         In these circumstances lenses of the best qualityshould be used. Cheap sunglasses, besides distorting the image, cannot be relied upon to give adequate protection from excessive ultraviolet radiation. (Page 51)"

Book: Barnes, Jonathan. Improve Your Eyesight: A Guide to the Bates Method for Better Eyesight without Glasses. Souvenir Press, 1999.


Problems with Habitual Use

·         "The person who needlessly wears sunglasses will habitually be using too few cones in his retina. In time he becomes so adapted to dim light that exposure to the sun results in discomfort or even pain. The effect this has on accurate vision will be appreciated when it is remembered that the fovea contains only cones.

·         This type of photophobia is brought about simply by bad use. In the study of physiology there is an axiom which states: 'Use makes the organ', or, more succinctly put, 'Use it or lose it'. Later we will see that this applies not only to light/dark adaptation, but also to the other functions of the eye-including accommodation. (Page 27)"

Book: Barnes, Jonathan. Improve Your Eyesight: A Guide to the Bates Method for Better Eyesight without Glasses. Souvenir Press, 1999.



Avoid too much sunlight. Exposure to some sunlight is good for your health, but too much sunlight can make your eyes tired, and can cause your brain to release endorphins and produce serotonin.

While light therapy can be helpful for people with SAD, too much serotonin is not desirable.


The 'Sunning' Exercise

·         Bates Method: Sunning


Tinted Glasses


Note: Tinted glasses are also manufactured for people who do not require corrective lenses.

      I decided to have my glasses tinted, after learning that anti-glare lenses actually let _more_ light through a lens than untreated glasses. I was told that letting more light through the lens is what reduces the glare.

      Surprisingly, it only cost $15.00 (USA) to have my glasses tinted, and it only took a few minutes to apply the tint.

      The tint I chose was a light brown color. Some tints, such as light brown, are desirable because they very slightly alter the perception of color. Other tints, such as light blue, have a greater effect on color.

       More information about lenses with tints can be found in the section 'Lenses with Tints' of the article:

All About Vision: Color Lenses and Photochromics (‘Lenses with Tints’ section)



·        Nutritonal Optometry: Functional Photophobia: Treatment: Tinted Lenses


UV-Blocking Lenses

“Studies have shown the spectrum of sunlight from ultraviolet and infrared portions of light produce varying degrees of ocular damage under accelerated testing. This research led to the important role played by UV blocking lenses.”

Melanin Vision Center: The Melanin Story


Blue-Blocking Lenses

“The next significant role to selective filters was the introduction of blue blocking lenses which emphasized on glare reduction and contrast enhancement with the removal of blue light rather than photoprotection.”

Melanin Vision Center: The Melanin Story


“…the blue, violet and other colors in the light spectrum penetrate the lens and reach the retina.

·        These high-energy visible rays can lead to Macular Degeneration. We need to go beyond UV and reduce these other rays.

·        Melanin glasses with their higher EPF [eye protection factor] values transmit less high-energy visible light and provide more protection to the retina.”

Melanin Vision Center: The Melanin Story



*EPF Value

% Transmission



19 %

Ray Ban G-15






Transitions (Gray)



Melanin Vision Center: The Melanin Story



EPF Number



Eagle Vision






Ray Ban (G-15 Lens)




Southwest Low Vision, Inc.: Sun Wear

”The numbers [above] have the same meaning as the SPF factor has for cosmetic creams. It means that in the case of melanin and Ray Ban lenses, one can stay out in the sun about 4 times longer with melanin than with Ray Bans, to get the same amount of eye damage to the retina.”

Southwest Low Vision, Inc.: Sun Wear


“Lenses tinted

·        yellow,

·        brown, or

·        amber [red also, see below]

absorb blue light and enhance contrasts in haze or fog.”

Baptist Memorial Health Care: Sunglasses - More than Fashion


“The red filter increases the contrast It absorbs all colours except red. A blue sky appears almost black, giving clouds a very dramatic appearance. Green areas, such as leaves or grass, are reproduced in very dark shades, so that red subjects are greatly contrasted with these areas. Red filters are also frequently used together with infrared film.” Nikon Filters (camera filters)


Things to Consider

Large Sunglasses:

“Large sunglasses are better than small ones because they protect against light coming in from the sides, top, and bottom of the frames. Glasses that slip even a quarter inch from the forehead allow about 20 percent more UV rays into the eyes.”

Baptist Memorial Health Care: Sunglasses - More than Fashion


Testing for Distortion:

“Be sure to test sunglasses for distortion. Hold them at arm's length and look at a straight line in the distance. If the line sways or bends when the glasses are slowly moved, the lenses are of poor quality.”

Baptist Memorial Health Care: Sunglasses - More than Fashion



·        Polarized lenses are good for cutting reflected glare.

·        Mirrored lenses reflect light and are good for water and snow sports.

·        Photochromic lenses respond the intensity of UV light by lightening or darkening according to brightness.

·        Gradient lenses are darker at the top than at the bottom.

Each of these lenses must be specially treated to guard against UV rays and blue light.”

Baptist Memorial Health Care: Sunglasses - More than Fashion


Red-Tinted Lenses:

·        Arousal: Perception of Color


Preserving Color Perception:

“The reduction of HEV [high energy visible light] (by the use of sunglasses and computer glasses) opens up a new lens challenge: the preservation of color perception. This paper also describes the new tests that show how melanin lenses used in (sunglasses and computer glasses) reduce HEV light without disturbing color perception.”

Melanin Vision Center: The Melanin Story


More Information about Melanin:

·        Research Topics: Melanin


Corrective Lenses:

Note: Computer lenses are also corrective lenses, usually.

·        Vision: Bates Method: The Problem with Corrective Lenses



·         Vision: Binocular Functions: Amblyopia


Problems with Glasses:

·        Vision: Bates Method: The Problem with Corrective Lenses: Effects of Glasses



Note: If you search Froogle for

Plastic and glass tinted glasses can usually be found in supermarkets and drug stores.

     Fancier glasses, specially made for computer users, can be found for sale on the Internet.

· Computer Glasses

·        Froogle Search: "computer glasses"

·        Nannini: Computer Glasses

·        Froogle Search: +glasses +melanin

·        Froogle Search: +sunglasses +melanin (more results than ‘+glasses +melanin’ search)

· Melavision Eyeware (Note: The word ‘eyeware’ is misspelled)

·        Debby Burk Optical: Computer Eyeglasses (some of these are non-prescription glasses)



“We had 25 golfers use the Melanin sun glasses [from the Melanin Vision Center] for two months during their rounds of golf. They were also encouraged to use them during other everyday activities. We then had them rate several criteria on a scale of 1 to 10 (with 10 being best). Following is the summary of the results.

(1) Quality: Averaged an excellent 8.8
(2) Appearance and Style: scored a 7.9
(3) Durability: was an impressive 8.7
(4) Comfort: averaged an 8.1
(5) Fit: scored an 8.0
(6) Eased eye strain: received an 8.5
(7) Preserved color: rated an 8.3
(8) Reduce glare: averaged a strong 8.6
(9) Overall Rating: was a very solid 8.6

Many of the golfers who participated in the test made comments indicating that wearing the Melanin sun glasses helped them play better golf.

     After reviewing the test results GolfTest USA feels that the Melanin sun glasses are quality sun glasses whose protection, appearance, fit, and durability makes these sun glasses a good value for golfers who want to play better golf and improved protection from the sun’s harmful effects.”

GolfTest USA: Melanin Sun Glasses: Test and Review / September, 2004


Things to Avoid  

If the tint of your glasses is too dark it can make you tired. If this happens you may find yourself becoming more dependent on the adrenaline that comes from viewing bright light, such as your computer screen. This can also cause problems for people with hyperacusis, since becoming tired means becoming more sensitive to noise.


Related Topics

·        The Brain: Serotonin Irritation Syndrome (SIS)

·        Vision: Binocular Functions: Problems with Binocular Functions



Back to 'Binocular Functions'