The microscopic examination of a planar sample in an oblique manner is proved to be feasible, indeed easy, using in conjunction with a microscope a simple attachment consisting of a unity magnification system and a diffraction grating.The illumination must be monochromatic.The unity magnification system focuses the sample onto the grating. The grating is chosen such that the first diffracted order corresponding to the incidence used in the arrangement is perpendicular to the grating. The grating is observed with the microscope in the conventional manner.The principle, properties, capabilities and limitations of this novel and versatile optical arrangement are explained and reviewed.

We describe the structure and function of a delivery system designed for use with an argon fluoride excimer laser for corneal surgery. The basic principle of the delivery system is to shape the laser beam with a slit mask to a defined configuration. The image of the slit is moved across the cornea in a mathematically defined pattern to ablate a given amount of tissue, creating a new anterior radius of curvature for the cornea. The location of the beam on the cornea is determined by a rotating dove prism and a translating spherical lens, each of which is controlled by computer-regulated servomotors. The system is versatile and can be used for laser myopic or hyperopic keratomileusis, for correction of astigmatism by surface ablation, for creation of radial or transverse linear cuts, for excision of corneal buttons, and for uniform lamellar corneal smoothing procedures. The delivery system is currently used in the laboratory for the ablation of nonhuman primate corneas.

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