Purpose: To evaluate a pro re nata administration of Ozurdex® implant versus a single administration for treating diabetic macular oedema (DME). Methods: This exploratory study is designed as a comparative, multicentre, randomized study with a follow-up of 6 months. Patients with DME were assigned to treatment at baseline either with a single Ozurdex® implant during the entire six-month follow-up (fixed group) or Ozurdex® implant followed by retreatment on an individualized basis (PRN group). Patients were scheduled for monthly evaluation based on assessment of best-corrected visual acuity (BCVA) and optical coherence tomography. Results: Twenty eyes were enrolled to the PRN group, and 22 were included in the fixed group. Following an equally steady, initial gain up to month 1, and maintenance up to month 3, vision started to decline in the fixed regimen group. At 6 months, a difference of 0.11 logMAR in BCVA was observed in favour of the PRN group. Compared to baseline, a significant reduction in retinal thickness was achieved up to month 2, when the fixed regimen group had begun to revert to pretreatment level. At 4 and 5 months, the difference in thickness between the two groups was statistically significant (p < 0.05). Mean number of treatments was 1.6 in the PRN group. Both fixed and PRN administration of Ozurdex showed a good safety profile. Conclusion: A personalized treatment with monthly monitoring and retreatment as needed is effective in maintaining functional and anatomical benefits of Ozurdex®
