Proactive treatment regimen with dexamethasone implant for diabetic and post-occlusive macular oedema: the ProDEX-2 study

Purpose: To evaluate the efficacy of proactive treatment with intravitreal dexamethasone implant (DEX-implant) at fixed 4-month intervals in treatment-naïve patients with diabetic macular oedema (DMO) and retinal vein occlusion (RVO), stratified by baseline visual acuity. Methods: Sixty-one treatment-naïve eyes (35 DMO, 26 RVO) received DEX-implant at 4-month intervals with possible adjustment (3.5–4.5 months) based on anatomical response. Patients were stratified by baseline visual acuity (<55 vs ≥55 Early Treatment Diabetic Retinopathy Study (ETDRS) letters). Main outcomes included changes in visual acuity, central subfield retinal thickness (CST), macular oedema recurrence rates and OCT qualitative parameters at 12 months. Results: Mean visual acuity improved from 51.9±21.1 to 57.8±15.7 ETDRS letters at month 12 (p<0.001). Patients with lower baseline visual acuity showed greater improvement (+8.5±7.8 letters) compared with those with higher baseline acuity (+2.7±6.1 letters, p=0.004). Mean CST decreased from 549.5±196.4 µm to 388.0±158.7 µm (p<0.001). At month 12, 47.5% of eyes maintained optimal or excellent anatomical response, allowing standard or extended intervals. The proactive approach prevented visual acuity and CST fluctuations. Multivariate analysis identified baseline hyperreflective foci count as the strongest positive predictor of visual improvement (β=0.24, p<0.001), while older age was negatively associated (β=−0.14 per 10 years, p=0.018). Conclusions: Proactive treatment with DEX-implant provided significant functional and anatomical improvements in treatment-naïve DMO and RVO patients while preventing deleterious visual acuity and CST fluctuations. Patients with lower baseline visual acuity and higher hyper-reflective foci count demonstrate greater potential for improvement, supporting this approach as an effective strategy, particularly in these subgroups.