Early Response to Intravitreal Dexamethasone Implant Therapy in Diabetic Macular Edema May Predict Visual Outcome

Purpose To determine whether early visual acuity response to intravitreal dexamethasone implant therapy in diabetic macular edema (DME) is associated with long-term outcome. Design Retrospective case series. Methods Multicenter (8 sites) retrospective review of medical records of eyes with DME treated with 0.7 mg intravitreal dexamethasone implant and minimum 18-month follow-up. One hundred and two eyes were included. Eyes with vitreoretinal interface abnormalities or that had undergone vitrectomy were excluded. Eyes were categorized into 3 groups based on change in best-corrected visual acuity (BCVA) at 3 months (logMAR equivalence of <5-letter, 5-9-letter, or ≥10-letter gain). Visual acuity outcomes were determined for each early response group. The relationship between early (3-month) and overall change in BCVA was assessed using regression analysis. Results In the study population (102 eyes), <5-letter, 5- to 9-letter, and ≥10-letter BCVA improvements were seen in 44.1%, 18.6%, and 37.3% of eyes, respectively, at 3 months. Among suboptimal (<5-letter) responders at 3 months, 6.7% showed ≥10-letter gains at study conclusion compared to 29% in the robust (≥10-letter) early response group (P =.009). Change in BCVA at 3 months showed significant positive correlation with overall change in BCVA (coefficient = 0.44, P =.002). Conclusions A similar proportion of eyes demonstrated suboptimal (<5-letter) and robust (≥10-letter) early response to treatment at 3 months. Eyes with a robust early response demonstrated ≥10-letter long-term gain in BCVA at a significantly higher rate compared to those with poor early response. Early treatment response directly correlated with overall change in BCVA.