Light Therapy
and Eye Safety
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The Lo-LIGHT Therapy Lamp |
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Can Bright Light Therapy Damage the Eye?
Researchers have expressed concern regarding the use of bright light
therapy because the visible blue light wavelengths emitted by these
bright light therapy lamps may cause retinal damage and could contribute
to the development of age related blindness.
This follows earlier cautions that users
of bright light therapy lamps be screened by ophthalmologists, and
that persons with
pre-existing retinal conditions or other risk factors abstain from
treatment or be closely monitored
The patented light therapy technology used in a Lo-LIGHT therapy lamp eliminates this potential risk of retinal damage associated with "bright light" therapy lamps. Lo-LIGHT lamps are effective at normal indoor intensity. Lo-LIGHT therapy lamps also screen out the hazardous blue wavelengths of visible light that present the risk of damage to the retina.
People using "Bright Light" therapy while taking photosensitizing medications
suffer an increased risk of eye damage. These medications, which sensitize the eye
to damage by visible light, include nonsteroidal anti-inflammatory drugs (NSAIDs), most antidepressants,
some antibiotics, diuretics, beta-blockers and other heart medications. Guidelines have been established
recommending that "Bright-Light" therapy not be used with these
photosensitizing medications.
A case report in the American Journal of Psychiatry described
a person who combined the use of "Bright Light" therapy and an
antidepressant medication. After five days of using light therapy
this patient suffered a "marked reduction in
visual acuity contrast sensitivity." Retinal examination found lesions in the
retinas of both eyes.
Other people, apart from those taking photosensitizing medications,
should be particularly cautious about using "bright light" therapy.
These include people with a pre-existing ocular condition or a susceptibility for retinal damage, such
as those with diabetes. Older people should also be
wary of bright light therapy. As we age, we experience a increased susceptibility to light-induced damage in retinal tissue,
which results from an age-related decline in the ability of retinal defense mechanisms to repair oxidative damage. This
susceptibility increases the risk in older people of retinal damage and permanent blindness.
Exposure to blue visible light causes oxidative damage in the retina.
Oxidative debris that results from this damage accumulates in the retina
over a lifetime and is related to the development of age-related
blindness. By age 75, more than one in every three people has Age-related
Macular Degeneration (AMD), and this increases to over one half of people by age
85.
It is worth considering what Herbert Kern, the first person to use bright light therapy, and therefore
the person with the longest history of bright light therapy use, said in the Sept 14, 2007 issue of Science
regarding his developing AMD. After explaining that light therapy became less and less effective for him
over the years as his eyesight faded, he said "Now I can hardly see, and all hell has broken loose" "I have
had periods of depression lasting over a year, and highs lasting as long."
See
Part II - Light exposure and AMD:
FOR THERAPISTS AND EYE SAFETY EXPERTS: In the past two years a growing understanding of wavelength sensitivity in light therapy has led to speculation regarding the practicality of using blue light therapy. For a more detailed discussion regarding the risk of retinal damage from blue light therapy click
