The present invention provides a method for the treatment of ocular or dermal diseases and/or conditions, e.g. an aqueous deficient dry eye state, uveitis or phacoanaphylactic endophthalmitis in an eye, or balanitis, psoriasis, or atopic dermatitis of the skin, said method comprising administering, topically to the eye or the skin, a therapeutically effective amount of a novel cyclosporin A derivative selected from the group consisting of compounds represented by the formula: wherein R1 is S-Alk-R wherein Alk is an alkylene linkage, preferably a methylene or poly methylene linkage, e.g. a C2 to C6 polymethylene linkage, or a polyalkenylene linkage, e.g. a C3 to C6 alkenylenyl linkage, R is R is —N═C(NR3R4)(NR5R6) or —NR7[(NR3R4)C═NR5], i.e. guanidines or —N═C(R8)(NR9R10), i.e. amidines wherein R3-R10 is H, Alk, Ar or (CH2)nAr wherein Ar is an aryl group and n is an integer of from 1 to 13 or R3 and R4 or R4 and R5 or R5 and R7 or R3 and R7, or R9 and R10, together may be —CH2—CH2— or —CH2—CH2—CH2— and R2 is selected from the group consisting of hydroxyl, lower alkyl and hydroxyl-substituted lower alkyl and R2 is selected from the group consisting of hydroxy and lower alkyl.