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Section IV

Laser Bio-Effects

The site of damage and threshold at which damage occurs depends on the wavelength, whether it is a small or extended source, the exposure duration, whether it is continuous wave or pulsed, and, if pulsed, the pulse length and pulse repetition frequency.

Operating lasers under reduced external light conditions increases the optical hazards because of pupil dilation.

The Maximum Permissible Exposure (MPE) is the level of laser radiation that a person may be exposed to without experiencing adverse health effects. Contact the LSO Valerie Perez for assistance in calculating the MPE.

  1. Eye
    Bio-effects of the eye are summarized in the following table:

    UV-C (200-280 nm) Cornea Photokeratitis
    UV-B (280-315 nm) Cornea Photokeratitis
    UV-A (315-400 nm) Lens Cataract
    Visible (400-780 nm) Retina Retinal injury*
    IR-A (780-1400 nm) Retina, Lens Retinal burn, cataract
    IR-B (1400-3000 nm) Cornea, Lens Corneal burn, cataract
    IR-C (3000-1000000 nm) Cornea Corneal burn
    * Retinal injury can be thermal, acoustic or photochemical.
  2. Skin
    Bio-effects of the skin are summarized in the following table:

    UV-C (200-280 nm) Erythema, cancer, accelerated aging
    UV-B (280-315 nm) Erythema, increased pigmentation, cancer, accelerated aging
    UV-A (315-400 nm) Erythema, increased pigmentation, skin burn
    Visible (400-780 nm) Photosensitive reactions, skin burn
    IR-A (780-1400 nm) Skin burn
    IR-B (1400-3000 nm) Skin burn
    IR-C (3000-1000000 nm) Skin burn

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