Aim Macular traction may influence the formation and response to treatment of diabetic macular oedema (DME). The aim of this study was to determine the prevalence and associations of spectral domain optical coherence tomography (SD-OCT) evident epiretinal membrane (ERM) and/or partial vitreomacular separation (pVMS) in consecutive patients undergoing macular photocoagulation for centre involving DME.

Methods A single-centre retrospective cross-sectional observational study.

Results 198 eyes of 198 patients were included. Twelve per cent of eyes demonstrated pVMS and 14% ERM. All cases of pVMS had vitreoretinal adhesion located in the Early Treatment Diabetic Retinopathy Study grid central 1 mm subfield. In 2/3 of ERM cases, ERM was either found in the central subfield or the thickening associated with ERM was contiguous with the thickening in the central subfield. Patients with signs of ERM or pVMS were significantly older and had significantly worse acuity than those without (mean age 67.2 vs 62.8 years (p=0.02); 0.49 vs 0.31 logMAR, p=0.0006). Macular thickness was similar in both groups. The prevalence of pVMS and/or ERM were 31% in Caucasian, 5% in Asian and 24% in Afro-Caribbean subjects (p=0.11).

Conclusions ERM or pVMS was found on SD-OCT scanning in 25% of patients undergoing laser for centre involving DME. In 20% of all patients, these potentially tractional elements were either present in the central subfield scan or the traction was contiguous with the central macular thickening, suggesting a possible role for surgical or enzymatic relief of traction in their management. This requires targeted investigation.