Pegaptanib for Retinal Edema Secondary to Diabetic Vascular Disease(Preserve) Study

Inclusion Criteria: 1. Subjects must have macular edema that involves the center of the macula with corresponding leakage on fluorescein angiogram. 2. Foveal thickness of at least 250 microns (OCT center point thickness), with a standard deviation of the center point of \<10%, an OCT signal strength of \> 5, and properly drawn ILM and RPE borders. 3. Best corrected distance visual acuity in the study eye must 137 be a letter score between 70 and 20 inclusive (20/40 to 20/400 Snellen equivalents). 4. Clear ocular media and adequate pupillary dilatation to permit good quality stereoscopic fundus photography. 5. Intraocular pressure (IOP) of 21 mmHg or less (local anti-hypertensive medication of any duration permitted). 6. The treating ophthalmologist should be comfortable that focal laser (direct and grid as needed) can be deferred for at least 18 weeks in the study eye, even though focal laser is indicated. 7. Type I, or Type II diabetic subjects, of both genders, and aged 18 years. 8. Women must be using effective contraception, be post-menopausal for at least 12 months prior to trial entry, or surgically sterile. All women of childbearing potential must have a negative serum pregnancy test at baseline and negative urine pregnancy tests immediately prior to each injection and use two effective forms of contraception during the trial and for at least 60 days following the last dose of pegaptanib sodium. 9. Ability to provide written informed consent. 10. Ability to return for all study visits. Exclusion Criteria: 1. Eyes in which panretinal photocoagulation is needed now or is likely to be needed within the next 6 months. 2. Eyes that have active PDR with high risk characteristics (HRC) as defined by the DRS: 1. Mild neovascularization of the disc (NVD) of at least 1/3 disc area as shown in standard photograph 10A of the DRS. 2. Moderate neovascularization of the retina elsewhere (NVE) of at least 1/2 disc area as shown in standard photograph 7 of the DRS. 3. Presence of any abnormality that is likely to confound assessment of visual acuity improvement in eyes in which macular edema resolves, or improves, such as non-perfusion for \>1 disc area involving the foveal avascular zone, epiretinal membrane associated with signs of contraction and/or significant opacification, or presence of chorioretinal atrophy involving the center of the macula. 4. Vitreomacular traction determined clinically and/or by OCT, which, in the investigator's opinion, contributes to the macular edema (or causes associated foveal detachment), and would preclude improvement with pegaptanib sodium 5. Any other cause of macular edema such as vitreous extension, or entrapment to anterior segment wound, or any retinal vein occlusion involving the macula. 6. Any subfoveal hard exudates, or RPE atrophy; or any present evidence, or past documentation of a foveal cyst (by fundus examination, FA or OCT). 7. Previous treatment with intravitreal corticosteroids in the study eye within 3 months of Day 0 visit. 8. Previous treatment with intravitreal anti-angiogenic drugs in the study eye within 3 months of Day 0 visit. 9. Previous PRP laser treatment in the study eye within 90 days of Day 0 visit. 10. Subjects who have received YAG laser or peripheral retinal cryoablation or laser retinopexy (for retinal tears only), or focal photocoagulation within the previous 16 weeks.