[An experimental study of diode laser photocoagulation and indocyanine green dye-enhanced diode laser photocoagulation in the primate retina].

A diode laser, emitting light in the near-infrared range (803 nm), was used for photocoagulation at mild, moderate, and strong intensities with or without intravenous administration of indocyanine green (ICG) in 7 eyes of 4 rhesus monkeys. The retinochoroidal lesions were studied histopathologically from 24 hours to 3 months after treatment, and choroidal vascular casts were studied by electron microscopy. Mild diode laser burns caused occlusion of the choriocapillaris and slight outer retinal damage. Moderate and severe burns caused more marked occlusion of the choriocapillaris, deep choroidal vessels, and choroidal nerves. There was little difference between ICG-enhanced and non-enhanced mild burns, but ICG-enhanced moderate and severe burns showed larger retinochoroidal lesions and more complete obstruction of the choriocapillaris than did burns without ICG enhancement. It seems that at moderate and strong levels, ICG-enhanced diode laser burns have more apparent effect on the retina and choroid, particularly on the choroidal vessels.