Laser-induced retinal damage threshold measurements with wavefront correction

An adaptive optics (AO) system was incorporated into a laser retinal exposure setup in order to correct for refractive error and higher-order aberrations of the nonhuman primate (NHP) eye during an in vivo retinal ED50 measurement. Using this system, the ED50 for a 100-ms, 532-nm small spot size exposure was measured to be 1.05 mJ total intraocular energy (TIE), a reduction of 22% from the value measured without aberration correction. The ED50 for a 3.5-ns, 532-nm exposure was measured to be 0.51 mu J TIE, the lowest ED50 reported for a ns-duration exposure. This is a reduction of 37% from the value measured without aberration correction and is a factor of only 2.6 higher than the maximum permissible exposure (MPE) for a 3.5-ns, visible wavelength small spot size exposure. The trend of in vitro measurements using retinal explants suggests that the in vivo ED50 for small spot-size exposures could potentially be one order of magnitude smaller than the previously reported in vivo ED50. Distortion of the incident laser beam by ocular aberrations cannot fully explain the discrepancy between the in vivo measurements with no aberration correction and the in vitro results. (C) 2008 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3013455]