Interdigitation Zone Band Restoration After Treatment of Diabetic Macular Edema

To investigate whether the integrity of the interdigitation zone band, the ellipsoid zone band, and the external limiting membrane are reliable markers of treatment outcome in diabetic macular edema (DME).

In this retrospective study, we examined 41 treatment-naïve eyes (38 patients) with DME that were treated with laser therapy, pharmacotherapy, and/or vitrectomy. Best-corrected visual acuity and the integrity of the interdigitation zone band, the ellipsoid zone band, and the external limiting membrane were assessed before treatment and at 3, 6, and 12 months after DME treatment.

One year after treatment, the external limiting membrane, ellipsoid zone band, and interdigitation zone band were completely visible in 30 (73.2%), 24 (58.5%), and 2 (4.9%) eyes, respectively. Interdigitation zone band status improved significantly (P = 0.005) 1 year after treatment. The interdigitation zone did not improve in the absence of the ellipsoid zone band. Likewise, ellipsoid zone status did not improve in the absence of the external limiting membrane at any time after treatment.

The results of this study show that restoration of the interdigitation zone band constitutes a very sensitive marker of DME treatment outcome when the ellipsoid zone band is visible before treatment.