Abstract: A method for coating silicon oxide SiO film and silicon dioxide SiO.sub.2 film on the surface of transparent optical material of glass or syntheic resin whose refractive indices are varied by changing the condition of vapor-deposition, under a predetermined condition of vapor-deposition so as to form a firm and durable anti-reflection film.

Abstract: A soft contact lens having a water content of at least 45% and a tensile strength of at least 100 g/mm.sup.2 can be produced by pouring into a mold a composition consisting of 70 to 93% by weight of an alkylene glycol monoacrylate or monomethacrylate, 0.3 to 2.0% by weight of a polyfunctional monomer, 1 to 10% by weight of a monomer having at least one carboxyl group in its molecule and 5 to 20% by weight of an acrylic or methacrylic acid derivative, raising the temperature of the composition from 35.degree. C to 110.degree. C continuously to effect polymerization, processing the resulting formed product into a lens, and then swelling the lens thus obtained by hydration treatment including alkali treatment.

Abstract: A reversible light-sensitive glass, e.g., for eyeglasses, comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO.sub.2, 15 to 22% B.sub.2 O.sub.3, 0 to 11% Al.sub.2 O.sub.3, 0 to 10% ZrO.sub.2, 6<Al.sub.2 O.sub.3 + ZrO.sub.2 <13%, 6 to 16% R.sub.2 O where R represents Li, Na or K, 0.5 to 7% BaO, BaO/R.sub.2 O 0.035 to 0.65, 0 to 2% TiO.sub.2, 0 to 2.5%Nd.sub.2 O.sub.3, 0 to 2.5% Ho.sub.2 O.sub.3, 0 to 2.5% Er.sub.2 O.sub.3, 0.2<Nd.sub.2 O.sub.3 + Ho.sub.2 O.sub.3 + Er.sub.2 O.sub.3 <2.5% and 0.002 to 0.03%CuO, and as light-sensitive components 0.15 to 1.0 part of Ag and more than the Ag chemical equivalent of halogens selected from the group consisting of Cl, Br and I.