The Effect of DA9301 on Tablet Computer-Induced Asthenopia

Inclusion Criteria: 1\. Healthy subject aged 20 to 65 years with more than 2 hours of daily use of a smart phone or computer including a tablet and television Exclusion Criteria: 1. Ocular disease in either eye * Ocular surface disease * Best corrected visual acuity \< 20/30 * Intraocular pressure \> 21 mmHg * Optical coherence tomography proven retinal nerve fiber defect * Significant cataract (lens opacities classification system III) * Significant entropion or ectropion * Significant tear drainage problem proved with fluorescein dye dilution test 2. Soft or Hard contact lens use 3 or more days a week 3. History of oral intake of health supplement designed to improve asthenopia within 4 weeks before participating this study 4. Pregnant woman 5. Systemic disease * Uncontrolled hypertension (systolic /diastolic blood pressure \> 140/90mmHg) * Uncontrolled diabetes mellitus (fasting blood glucose level \> 180mg/dL) * Rheumatoid arthritis * Malignant disease * Active hepatitis (type B and C) * Acute or chronic infectious disease * Renal disease