Evaluation of the changes of quantity and quality of tears by rebamipide sodium instillation

INTERVENTION: Instillation (rebamipide) Instillation (artificial tear) CONDITION: Dry eye PRIMARY OUTCOME: Tear film breakup time, corneal and conjunctival epithelial damage score, tear meniscus radius, Schirmer test(I), spreading velocity of tear film lipid layer, questionnaire(VAS score) INCLUSION CRITERIA: 1. Normal subject (20 persons) without following 1)‐4) 2. Aqueous tear deficient dry eye patients (20 persons) with following 1)‐3). 3. Evaporative dry eye patients (20 persons) with following 2) and 3). 4. Short BUT type dry eye patients (20 persons) with following 2) who have symptoms not responsible for conventional instillation treatment 1) Schirmer test (I) <= 5mm 2) Tear film breakup time <= 5 seconds 3) Positive vital dye staining of cornea and conjunctiva (Fluorescein, Lisamine green) (more than 3, maximum=9)