Abstract: The invention features improvements in PRK procedures that relate to preventing non-uniform removal of material from the corneal surface. It has been realized that photoablation by-products resulting during the PRK procedure can affect the accuracy and the predictability of the procedure. Under certain conditions, the plume of photoablation by-products that have left the corneal surface can non-uniformly redeposit onto the ablation area and thus affect the uniformity of subsequent material removal. The plume of photoablation by-products, in the space above the corneal surface, can also non-uniformly affect the escape of further photoablation products from the surface. In addition to the plume effects, it has been realized that the hydration level of the corneal tissue during the PRK procedure can vary over the ablation area and likewise non-uniformly affect the PRK procedure.

Abstract: For a selected collar stay, i.e., 0.375 inches in width, for a shirt knitted with selectively sized wales, i.e., 0.10 inches in width, a pocket for the stay also knitted but with selectively narrower wales, i.e., 0.025 inches in width, so that predictably a number of wales, i.e., 14 in number, produces a width of the pocket approximately equal to the width of the stay to minimize movement of the stay within the pocket.