Research Study

Treatment for Central-Involved Diabetic Macular Edema in Eyes With Very Good Visual Acuity
Principal Investigator 
David Maberley


Body Locations and Systems 
Macular Edema
Disorders and Conditions 
Closed for Recruitment
Study Start/End 
Jun 20, 2014 to Dec 31, 2018
Vancouver General Hospital
Theresa Wiens, Clinical Trial Coordinator
604-875-4111 ext.62544
Purpose of Study 

Although multiple studies have clearly demonstrated that ranibizumab therapy is more effective than laser alone for vision gain and avoiding vision loss in patients with central-involved Diabetic Macular Edema (DME), only eyes with poor visual acuity, such as a visual acuity letter score of 78 or worse (approximate Snellen equivalent of 20/32 or worse) were eligible. Eyes that have central-involved DME with "good" visual acuity (20/25 or better) have not been addressed systematically by recent studies for treatment of DME. Baseline cohort characteristics from the Early Treatment Diabetic Retinopathy Study (ETDRS) suggest that a substantial percentage of eyes with central-involved DME may retain good vision. The investigators do not know definitively whether eyes with central-involved DME and good vision do better with anti-VEGF (vascular endothelial growth factor) (e.g. aflibercept) therapy initially, or focal/grid laser treatment or observation initially followed by anti-VEGF only if vision worsens.

The primary objective of the protocol is to compare the % of eyes that have lost at least 5 letters of visual acuity at 2 years compared with baseline mean visual acuity in eyes with central-involved DME and good visual acuity defined as a Snellen equivalent of 20/25 or better (electronic-ETDRS letter score of 79 or better) that receive (1) prompt focal/grid photocoagulation + deferred anti-VEGF, (2) observation + deferred anti-VEGF, or (3) prompt anti-VEGF.

Secondary objectives include:

  • Comparing other visual acuity outcomes between treatment groups, such as the percent of eyes with at least 5, 10 and 15 letter losses in visual acuity from baseline mean visual acuity, percent of eyes with at least 5 letter gain in visual acuity from baseline, mean visual acuity, mean change in visual acuity, adjusted for baseline mean visual acuity
  • For eyes randomized to deferred anti-VEGF, the percentage of eyes needing anti-VEGF treatment
  • Comparing optical coherence tomography (OCT) outcomes, such as the mean change in OCT central subfield (CSF) thickness, adjusted for baseline mean thickness
  • Comparing the number of eyes with PDR at randomization, proportion of eyes avoiding vitreous hemorrhage or panretinal photocoagulation (PRP) or vitrectomy for PDR between treatment groups
  • Comparing safety outcomes between treatment groups
  • Comparing associated treatment and follow-up exam costs between treatment groups

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