Singlet oxygen (Ag) has been produced in Freon 113 solution by pumping the oxygen Ag + lv<-3 452gẽ lectronic transition by 1.06 µ radiation from a continuous Nd-YAG laser or a Q-switched Nd-glass laser. The singlet oxygen thus produced was detected by reaction with the acceptor 1,3-diphenylisobenzofuran (DPBF) Comparison of the amount of DPBF concentration change with the amount of singlet oxygen produced has shown that the rate constant of reaction of DPBF with singlet oxygen obtained by Merkel and Kearns and others is an order of magnitude too high but corresponds to the total rate constant which we measure for reaction plus quenching. The rate of quenching of singlet oxygen by ground state oxygen has been measured to be 2.7 X 10s 1. mol-1 sec-1 in Freon 113, only twice the rate in the gas phase measured by Wayne and others.

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The corneal polarization cross can be seen at the human cornea using crossed polaroids. The optical mechanisms for this phenomena include rotation and retardation of the light at the surface of the cornea due to the corneal curvature, as well as retardation due to an average circumferential orientation of the birefringent corneal collagen.

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Plasma coating (deposition of polymer under the influence of plasma) is utilized to modify the surface properties of corneal contact lens. An ultrathin layer (thickness of roughly 200 A) of plasma polymer of acetylene/H20/N2 is applied to poly(methyl methacrylate) (PMMA) corneal contact lenses. The surface becomes highly wettable with water compared to uncoated lens. When coated and uncoated contact lenses are placed on rabbit eyes, a remarkable difference in accumulation of mucous matter is observed. With the control lenses, the accumulation of mucous matter in a week is sufficient to affect the optical clarity of the lenses, whereas the coated lenses show no change after three months continuous wearing. The comparative degree of adhesion of the corneal epithelium cells onto glass, modified glass, PMMA, and coated PMMA surfaces is studied using tissue cultures and phase contrast microscopy. The coated PMMA surface exhibits a degree of tissue adhesion lower than that of control PMMA and higher than that of glass surface, and no sign of toxicity of the coated surface is observed by the tissue cultures.