Laser injury


  • Use of lasers in civilian and military applications is increasing
  • Military use - range finders, target designators, guidance systems, non-lethal denial, and now being used as directed energy weapons
  • Civilian use - laser cutter/engraver, precision measurement, pointers, welding, entertainment
  • Potential to cause injury is largely dependent upon irradiance and beam wavelength
  • Irradiance
    • Amount of energy that hits the eye/skin per unit area
    • Dependent on output power, distance from source to target, and beam divergence
    • Human eye can focus laser to a very small area on the retina increasing the irradiance by a factor of 100,000

ANSI Classification of Laser

Class 1 - non-hazardous
Class 2 - visible laser, aversion response will protect
Class 3a - eye hazard with optical aids that collect or focus beam
Class 3b - eye hazard, some skin at high power
Class 4 - eye hazard, skin hazard, fire hazard, diffuse reflection hazard

Clinical Features


Main organ of concern; range of effects as below starting with the most severe to the least; damage from thermal / photochemical / photomechanical process

  • Tissue vaporization
  • Retinal hemorrhage / ocular holes
  • Retinal burn / corneal burn / irreversible scotoma/minimal visible lesion
  • Histological damage / irreversible scotoma / cataract
  • Nominal ocular hazard distance (NOHD)
    • Distance from laser source which the intensity of a single laser beam becomes safe by not exceeding the maximum permissible exposure
    • Laser is dangerous if viewed from a closer distance than this
    • Can be calculated if power (mW), divergence (mrad), and diameter at aperture (mm) is known
  • Flash blindness / after images / reversible scotoma
    • visual loss temporary
    • lasts seconds to minutes
    • similar to flashbulb effect
  • Glare/dazzle
    • no permanent damage results
    • similar to driving into the setting sun
  • Distraction


Second organ of concern; effect more dependent on wavelength of laser

  • thermal burns - IR, visible, UV-A laser
  • photosensitivity - Visible, UV-A laser
  • darkening - UV-A laser
  • accelerated skin aging - UV-B
  • skin cancer/erythema - UV-C

Differential Diagnosis


  • History
    • Obtain detailed information as to the nature and characteristic of the laser beam exposure
    • Intensity, color, constant or flicker, duration of exposure, location, beam diameter estimate, range, source, location, type of laser, class of laser
  • Examination
    • External exam of skin and adenxa looking for burns or evidence of physical trauma
    • Visual acuity near and far
    • Amsler grid test
    • Pupils
    • Stereopsis
    • Color vision
    • Slit lamp examination
    • Retinal (fundoscopic) examination


  • As appropriate per history and physical exam findings


  • Discharge home if normal exam and no persistent symptoms suggestive of laser eye injury
  • Consult ophthalmologist if persistent symptoms or positive findings on examination suggesting laser eye injury such as retinal hemorrhage, corneal burn, ocular holes, etc.

See Also