The present invention finds an effective treatment for glaucoma and provides it as a medicine.The combination of the present invention, particularly the combination of 2-propanyl 4-{(3S, 5aR, 6R, 7R, 8aS)-6-[(1E, 3R)-4-(2,5-difluorophenoxy)-3-hydroxy-1-buten-1-yl]-7-hydroxyoctahydro-2H-cyclopenta [b] oxepin-3-yl} butanoate and a β blocker is useful as a therapeutic agent for glaucoma because it has an effect of enhancing intraocular pressure lowering action and sustaining an intraocular pressure lowering action as compared with single agent administration of each drug.本發明發現一種有效之青光眼治療法，並提供為醫藥品。本發明之組合，尤其是4-{(3S,5aR,6R,7R,8aS)-6-[(1E,3R)-4-(2,5-二氟苯氧基)-3-羥基-1-丁烯-1-基]-7-羥基八氫-2H-環戊并[b]噁庚因-3-基}丁酸2-丙酯與β阻斷藥之組合，相較於各藥劑單劑投予時，具有眼壓降低作用增強且眼壓降低作用持續之效果，故作為青光眼治療劑為有用者。
