Light Therapy and Eye Safety

Can Bright Light Therapy Damage the Eye?

Experts are concerned that blue light wavelengths emitted from bright light therapy lamps contribute to the development of age related blindness. Refs. It is recommended users of blue or bright light therapy lamps be screened by ophthalmologists, and those with pre-existing retinal conditions not use bright light therapy treatment or be closely monitored. Refs.

People using Bright Light or Blue Light therapy while taking photosensitizing medications have an increased risk of eye damage. Medications that sensitize the eye to damage by blue light include nonsteroidal anti-inflammatory drugs (NSAIDs), antidepressants, antibiotics, diuretics, beta-blockers and other heart medications. Refs.

A case report in the American Journal of Psychiatry describes a person who combined bright light therapy and an antidepressant. 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. Ref.

People with increased risk of vision loss from bright or blue light therapy include those with diabetes and others with a heightened susceptibility of retinal damage. Older people are also more susceptible to retinal damage from blue light because of the age-related decline in retinal repair mechanisms that occurs after age 40. Refs.

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. AMD affects the vision of 14 million Americans and is the leading cause of irreversible blindness in developed countries. Ref.

The low intensity GreenLIGHT technology used in Lo-LIGHT therapy lamps eliminates the risk of retinal damage from the use of bright light or blue light therapy lamps. The Lo-LIGHT was found to be as effective as high intensity bright light therapy lamps by several leading independent light therapy experts. Lo-LIGHT lamps operate at normal indoor light intensity, and do not emit the hazardous blue wavelengths of visible light that can damage the retina.

AMD is more difficult for users of light therapy

Impaired vision can be particularly difficult for people suffering from depression. Herbert Kern, the first person to use bright light therapy, described in the journal Science how light therapy became less and less effective for him over the years as his eyesight faded because of his developing AMD. He explained, "Now I can hardly see, and all hell has broken loose" "I have had periods of depression lasting over a year...."
See Science; Is Internal Timing Key to Mental Health? last paragraph.

More technical information on light therapy and eye damage.

See Part II - Light exposure and macular degeneration