Effect of Dexamethasone Implant in Hard Exudate Complicated With Diabetic Macular Edema

Inclusion Criteria: 1. Patients diagnosed with CSME (clinically significant macular edema) with hard exudates within 1500 micrometer from foveal center 2. Those who have a BCVA (best corrected visual acuity) of study eye between 0.06(20/320) and 0.5(20/40) 3. Those who have a central macular thickness on OCT over 300 micrometer 4. If both eyes are eligible, eye having more hard exudates is selected (contralateral eye should be treated with corticosteroid other than Ozurdex or focal laser photocoagulation, anti-VEGF (vascular endothelial growth factor) injection is not allowed in contralateral eye) Exclusion Criteria: 1. Those who have CSME without hard exudates 2. Those who have macular edema not related with diabetic retinopathy (e.g. AMD (age-related macular degeneration), uveitis, retinal vein occlusion and untreated malignant hypertension) 3. Those who have a history of Intraocular surgery (e.g. cataract surgery) within 3 months 4. Those who have a visual acuity of contralateral eye less than 0.1 (10/100) 5. Those who received focal laser treatment on macula within 3 months 6. Those who had intravitreal anti-VEGF agent injection within 3 months 7. Those who had intravitreal triamcinolone injection within 6 months 8. Those who have other ophthalmologic disease affecting visual acuity (e.g. central corneal opacity, cataract change at lens center) 9. Those who have severe systemic disease (e.g. uncontrolled DM, hypertension, cardiovascular disease, cerebrovascular disease) 10. Those who refuse to submit written consent 11. Those who cannot understand the contents of the clinical study and cooperate in the clinical trial 12. Those who are pregnant or lactating women 13. Those who have a history of vitrectomy 14. Those who require systemic corticosteroid or immunosuppressive agent treatment 15. Those who are banned from using Ozurdex * Ocular infection or periocular infection * Advanced glaucoma * Hypersensitivity to dexamethasone or other component of Ozurdex * Posterior lens capsule rupture or Aphakia * Anterior chamber intraocular lens or posterior capsule rupture