Findings from this retrospective study suggest that patients with initial suboptimal response to an intravitreal corticosteroid implant may continue to have a suboptimal response on long-term follow-up.

Researchers reviewed medical charts from 102 eyes with diabetic macular edema that received a 0.7-mg dexamethasone intravitreal implant. Eyes were subdivided into 3 groups based on change in BCVA at 3 months. The investigators followed the patients for at least 18 months to assess the long-term outcomes of each group.

The analysis uncovered a significant, positive correlation between response at 3 months and long-term improvement in BCVA. Of the eyes with a >10 letter improvement in BCVA at 3 months, 29% maintained that improvement at final follow-up. By contrast, only 7% of eyes with a <5 letter improvement in BCVA gained more than 10 letters by final follow-up.

Retrospective chart reviews are inherently limited. Given the dexamethasone implant’s durability, excluding eyes with a history of vitrectomy may inadvertently exclude a large portion of the potential study population. Interestingly, the majority of eyes demonstrated either a >10 letter improvement or a <5 letter improvement (with few outliers), suggesting an alternative interpretation of the study’s findings: that diabetic macular edema may respond to intravitreal dexamethasone in an almost binary fashion.

This study suggests that a patient’s early response to the intravitreal corticosteroid implant may predict their long-term gains in BCVA. In clinical practice, these findings could indicate that eyes with poor initial response to intravitreal corticosteroids may be better served with alternative treatment modalities such as anti-VEGF therapy or early pars plana vitrectomy, although further study is warranted before making this conclusion.