The three-times-per-day eye dropping of the usage or dosage of the present invention i.e. 1.5% (w/v) levofloxacin eye drop cures bacterial conjunctivitis by a shorter period than the prior usage or dosage i.e. three-times-per-day eye dropping of 0.5% (w/v) levofloxacin eye drop, and yet own the characteristic of not increasing the incidence rate of side effect as well. Because to cure eye infection disease in short period is shortening the exposure period of eye infection disease inflammatory bacteria to levofloxacin, levofloxacin eye drop of the usage or dosage of the present invention, as a result, has been expected for inhibiting the occurrence of resistant bacteria caused by long-term usage of levofloxacin eye drop of the prior usage or dosage. Also, the levofloxacin eye drop of the usage or dosage of the present invention has been confirmed to directly inhibit the resistibilization of eye infection disease inflammatory bacteria of Staphylococcus aureus and the like caused by the short-term usage of levofloxacin eye drop of the prior usage or dosage.本發明之用法或用量之1.5%(w/v)左氧氟沙星點眼液之每日點眼三次，比以往之用法或用量之0.5%(w/v)點眼液之每日點眼三次以較短期間治癒細菌性結膜炎，並以副作用之出現率也不增大為特徵。因以短期間治癒眼感染症乃縮短眼感染症產生發炎菌與左氧氟沙星之曝露期間，故本發明之用法或用量之左氧氟沙星點眼液以結果而言，可期待抑制因長期使用以往用法或用量之左氧氟沙星點眼液之耐性菌之出現。又確認本發明之用法或用量之左氧氟沙星點眼液可將因以往用法或用量之左氧氟沙星點眼液之短期使用之金黃色葡萄球菌等眼感染症產生發炎菌之耐性化直接抑制。
