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

Abstract

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.