Oral Azithromycin Versus Doxycycline in Posterior Blepharitis

One hundred patients with the diagnosis of posterior blepharitis based on history taking and proper physical examinations by two experienced ophthalmologists will include in the study. Patients will diagnose with posterior blepharitis if they score at least one in two symptoms (based on a subjective grading scale) and two signs (based on an objective grading scale) of posterior blepharitis according to study criteria. Patients will exclude if they have the following criteria: age\< 12 years old,history of previous ocular or lacrimal surgery,previous usage of contact lenses,any history of ocular allergy,history of systemic diseases with ocular involvement (except rosacea), history of usage of topical or systemic antibiotic in the last month, pregnancy or lactating mothers, liver failure and any history of sensitivity to cyclines. Qualified patients then randomly receive oral azithromycin (2 of 250 mg capsules for the first day and 250mg for the next 4 days) or oral doxycycline (100mg capsule every 12 hours for one month) in a double-blinded fashion. each patients in both treatment groups will accurately instruct to apply warm compress and eyelid scrubbing 2 times a day for 5 minutes each in the treatment period. Symptoms and signs were recorded for each patient in two treatment groups at baseline visit (before treatment) and then in the days 7, 31, 37 and 61 after treatment.