Dose Ranging Study of an Ocular Sirolimus (Rapamycin) Formulation in Patients With Diabetic Macular Edema

Inclusion Criteria include but are not limited to: * Diagnosed with diabetes mellitus * Macular edema secondary to diabetic retinopathy * Visual acuity of 20/40 to 20/200 in study eye Exclusion Criteria include but are not limited to: * Any other ocular disease that could compromise vision in the study eye * Any of the following treatments to the study eye within 90 days prior to study start: intravitreal injections; posterior subtenons steroids; focal/grid macular photocoagulation; intraocular surgery * Capsulotomy of the study eye within 30 days prior to study start