A compound represented by the following Formula (I-a) or Formula (I-b) having a LogD value of more than 1.5 and less than 2.5, or a pharmaceutically acceptable salt thereof, for use in treating glaucoma or lowering intraocular pressure: wherein A is a C 1 -C 3 alkylene chain, in which one methylene group is optionally substituted by an oxygen atom or a sulfur atom; R a is a group selected from the following formulae: R b is a group selected from the following formulae: R 1a, R 2a, R 3a, R 4a, R 5a, R 1b, R 2b, and R 3b are a hydrogen atom, a halogen atom, an optionally substituted C 1 -C 6 alkyl group, a C 1 -C 6 alkoxy group, a C 3 -C 6 cycloalkyl group, a C 3 -C 6 cycloalkoxy group, a halo C 1 -C 4 alkyl group, an optionally substituted ethynyl group, an aryl group which is optionally substituted on an aromatic ring, an aryloxy group which is optionally substituted on an aromatic ring, a benzyl group which is optionally substituted on a benzene ring, a phenethyl group which is optionally substituted on a benzene ring, a benzyloxy group which is optionally substituted on a benzene ring, or a phenyloxymethyl group which is optionally substituted on a benzene ring; Ar b is an aryl group, or a heteroaryl group of a 5- or 6-membered ring containing a nitrogen atom, an oxygen atom, or a sulfur atom; X 1a and X 2a are independently from each other CH or a nitrogen atom; X b is a hydrogen atom or a halogen atom; Y 1a and Y 2a are independently from each other methylene, an oxygen atom, or a sulfur atom, but both of Y 1a and Y 2a are not a sulfur atom; Y b is a hydrogen atom, a C 1 -C 6 alkyl group, a halo C 1 -C 4 alkyl group, a cyano group, or a halogen atom; W b is CH or a nitrogen atom; l is an integer of 1 to 3, and when l is 2 or more, R 1b may be different from each other; m is 1 or 2; and n is an integer of 3 to 5. wherein A is a C 1 -C 3 alkylene chain, in which one methylene group is optionally substituted by an oxygen atom or a sulfur atom; R a is a group selected from the following formulae: R b is a group selected from the following formulae: R 1a, R 2a, R 3a, R 4a, R 5a, R 1b, R 2b, and R 3b are a hydrogen atom, a halogen atom, an optionally substituted C 1 -C 6 alkyl group, a C 1 -C 6 alkoxy group, a C 3 -C 6 cycloalkyl group, a C 3 -C 6 cycloalkoxy group, a halo C 1 -C 4 alkyl group, an optionally substituted ethynyl group, an aryl group which is optionally substituted on an aromatic ring, an aryloxy group which is optionally substituted on an aromatic ring, a benzyl group which is optionally substituted on a benzene ring, a phenethyl group which is optionally substituted on a benzene ring, a benzyloxy group which is optionally substituted on a benzene ring, or a phenyloxymethyl group which is optionally substituted on a benzene ring; Ar b is an aryl group, or a heteroaryl group of a 5- or 6-membered ring containing a nitrogen atom, an oxygen atom, or a sulfur atom; X 1a and X 2a are independently from each other CH or a nitrogen atom; X b is a hydrogen atom or a halogen atom; Y 1a and Y 2a are independently from each other methylene, an oxygen atom, or a sulfur atom, but both of Y 1a and Y 2a are not a sulfur atom; Y b is a hydrogen atom, a C 1 -C 6 alkyl group, a halo C 1 -C 4 alkyl group, a cyano group, or a halogen atom; W b is CH or a nitrogen atom; l is an integer of 1 to 3, and when l is 2 or more, R 1b may be different from each other; m is 1 or 2; and n is an integer of 3 to 5.