Early DMO: a predictor of poor outcomes following cataract surgery in diabetic patients. The DICAT-II study

Background: The prospective DIabetes and CATaract Study II (DICAT II) was performed to characterise the risks of cataract surgery to the retinae of patients with early diabetic macular oedema (E-DMO). Methods: DICAT II was a prospective, comparative, multicentre, observational study involving six Italian clinics. Patients were aged ≥55 years, had type 1 or 2 diabetes with spectral-domain optical coherence tomography evidence of ESASO classification Early DMO. Group 1 eyes (78 eyes, 78 patients) underwent phacoemulsification-based cataract surgery. Group 2 eyes (65 eyes, 65 patients) had E-DMO and either clear media or had undergone uncomplicated cataract surgery ≥1 year previously. Central subfield thickness (CST) and best-corrected visual acuity (BCVA) were assessed in both groups. Results: The negative impact of surgery on CST was evident after the first postoperative week; CST peaked during the first month, then rapidly decreased. CST worsening ≥10 µm was observed in 63/78 eyes (80.7%) and 29/65 eyes (44.6%) in Groups 1 and 2, respectively (p < 0.0001). CST worsening of ≥50 µm was observed in 51 eyes (65.4%) and 10 eyes (15.4%) in Groups 1 and 2, respectively (p < 0.0001). Mean CST worsening was lower in Group 2 than in Group 1 (38.6 ± 30.4 µm vs 85.5 ± 55.3 µm, p < 0.0001) with a lower BCVA loss (-2.6 ± 3.5 letters vs -8.2 ± 6.2 letters, p < 0.0001). Higher glycaemic levels and HBA1c levels were significantly associated with the risk of >50 μm CST worsening in eyes from both groups. Conclusion: Early DMO is associated with poorer outcomes after cataract surgery and requires close pre- and postoperative monitoring.