Application of optical transform techniques to laser irradiation of retina

Novel retinal irradiation techniques for laser damage studies are described; these are straightforward applications of the Fourier transform properties of an optical system. Interposing an appropriate diffracting screen between the laser source and the test eye enables one to simultaneously induce a number of discrete and precisely located retinal exposures with a known gradation of energy. Various kinds of diffracting objects are considered, and it is seen that transparent sinusoidal phase gratings offer the most promise for damage threshold studies. The method provides an objective measure of the ocular focal length at the time of the exposure. The production of arbitrary retinal irradiation patterns for more general research or clinical applications is possible with the extension of the technique by the use of simple holographic methods for forming the appropriate diffracting screens.