Since a compound represented by the general formula (I) (wherein definition of each group is as described in the specification), a salt thereof, a solvate thereof, or a prodrug thereof has strong and sustaining intraocular pressure lowering activity and, further, has no side effect on eyes such as ocular stimulating property (hyperemia, corneal clouding etc.), aqueous humor protein rise etc., it has high safety, and can be an excellent agent for preventing and/or treating glaucoma etc.

##STR00001##

Since a compound represented by the general formula (I) (wherein definition of each group is as described in the specification), a salt thereof, a solvate thereof, or a prodrug thereof has strong and sustaining intraocular pressure lowering activity and, further, has no side effect on eyes such as ocular stimulating property (hyperemia, corneal clouding etc.), aqueous humor protein rise etc., it has high safety, and can be an excellent agent for preventing and/or treating glaucoma etc.

##STR00001##

Provided is a monomer that improves solubility in organic solvents, hydrolyzability, and solubility in water after hydrolysis of a resin as well as imparts higher heat resistance to a resin. A resin for a photoresist containing a polymerization unit represented by Formula (Y), wherein R.sup.h represents a halogen atom or an alkyl group having from 1 to 6 carbons and having a halogen atom; R.sup.1 is a substituent attached to a ring and represents a halogen atom, an alkyl group that has from 1 to 6 carbons and may have a halogen atom, a hydroxyalkyl group that has from 1 to 6 carbons and may have a halogen atom and has a hydroxyl group moiety which may be protected by a protecting group, a carboxyl group that may form a salt, or a substituted oxycarbonyl group; A represents an alkylene group having from 1 to 6 carbons, an oxygen atom, a sulfur atom, or no bond; m is the number of R.sup.1 and represents an integer from 0 to 8; X represents an electron-withdrawing substituent; n is the number of X and represents an integer from 1 to 9; B represents a single bond or a linking group; and a steric position of a COOB-group attached to a polymer chain may be either endo or exo.

Provided is a monomer that improves solubility in organic solvents, hydrolyzability, and solubility in water after hydrolysis of a resin as well as imparts higher heat resistance to a resin. A resin for a photoresist containing a polymerization unit represented by Formula (Y), wherein R.sup.h represents a halogen atom or an alkyl group having from 1 to 6 carbons and having a halogen atom; R.sup.1 is a substituent attached to a ring and represents a halogen atom, an alkyl group that has from 1 to 6 carbons and may have a halogen atom, a hydroxyalkyl group that has from 1 to 6 carbons and may have a halogen atom and has a hydroxyl group moiety which may be protected by a protecting group, a carboxyl group that may form a salt, or a substituted oxycarbonyl group; A represents an alkylene group having from 1 to 6 carbons, an oxygen atom, a sulfur atom, or no bond; m is the number of R.sup.1 and represents an integer from 0 to 8; X represents an electron-withdrawing substituent; n is the number of X and represents an integer from 1 to 9; B represents a single bond or a linking group; and a steric position of a COOB-group attached to a polymer chain may be either endo or exo.