Purpose: To evaluate the effect of targeted retinal photocoagulation (TRP) on visual and anatomic outcomes and treatment burden in eyes with diabetic macular edema (DME). Design: Phase I/II prospective, randomized, controlled clinical trial. Participants: Forty eyes of 29 patients with center-involved macular edema secondary to diabetes mellitus. Methods: Eyes with center-involved DME and Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) between 20/32 and 20/320 (Snellen equivalent) were randomized 1:1 to monotherapy with 0.3 mg ranibizumab (Lucentis, Genentech, South San Francisco, CA) or combination therapy with 0.3 mg ranibizumab and TRP guided by widefield fluorescein angiography. All eyes received 4 monthly ranibizumab injections followed by monthly examinations and pro re nata (PRN) re-treatment through 36 months. Targeted retinal photocoagulation was administered outside the macula to areas of retinal capillary nonperfusion plus a 1–disc area margin in the combination therapy arm at week 1, with re-treatment at months 6, 18, and 25, if indicated. Main Outcome Measures: Mean change in ETDRS BCVA from baseline and number of intravitreal injections administered. Results: At baseline, mean age was 55 years, mean BCVA was 20/63 (Snellen equivalent), and mean central retinal subfield thickness (CRT) was 530 μm. Thirty-four eyes (85%) completed month 36, at which point mean BCVA improved 13.9 and 8.2 letters (P = 0.20) and mean CRT improved 302 and 152 μm (P = 0.03) in the monotherapy and combination therapy arms, respectively. The mean number of injections administered through month 36 was 24.4 (range, 10–34) and 27.1 (range, 12–36), with 73% (362/496) and 80% (433/538) of PRN injections administered (P = 0.004) in the monotherapy and combination therapy arms, respectively. Goldmann visual field isopter III-4e area decreased by 2% and 18% in the monotherapy and combination therapy arms, respectively (P = 0.30). Conclusions: In this 3-year randomized trial of 40 eyes with DME, there was no evidence that combination therapy with ranibizumab and TRP improved visual outcomes or reduced treatment burden compared with ranibizumab alone.
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