The Nature of Chorioretinal Lesions Produced by the Gallium Arsenide Laser

¹ Joint AMRDC-AMC Laser Safety Team, Frankford Arsenal, Philadelphia, Pa. 19137; Department of Pathology, Duke University Medical Center, Durham, N. C. 27706
² Joint AMRDC-AMC Laser Safety Team, Frankford Arsenal, Philadelphia, Pa. 19137

Technical modifications of the gallium arsenide laser have recently permitted its emission of sufficient power to produce ocular damage. The emitted radiation at 8,600 A is in the visible spectrum and, hence, primarily damages the retina. Ophthalmoscopically, the lesions are toroids of well-defined opacity surrounding small central circles of lesser opacity. The lesions are histopathologically characterized by extensive damage to pigment epithelium and outer retina. The damage is irregular, consisting of extensive damage at the periphery of the burns accompanied by relative sparing of the centers. Furthermore, damaged areas are circular despite an elliptical beam emitted from the laser. The lesions resolve by phagocytic removal of destroyed retina and by reconstitution of pigment epithelium; significant gliosis does not occur. These findings suggest the gallium arsenide laser damages the retina by thermal means, though producing peculiar lesions that are both circular and uneven.

Note:
In conducting the research described in this manuscript, the investigators adhered to the Guide for Laboratory Animal Facilities and Care, as promulgated by the Committee on the Guide for Laboratory Animal Facilties and Care of the Institute of Laboratory Animal Resources, National Academy of Sciences, National Research Council.