Increased choroidal thickness: a new indicator for monitoring diabetic macular oedema recurrence

The aim of this study was to determine whether choroidal thickness (CT) increases at the time of exudative recurrence in diabetic patients with unilateral diabetic macular oedema (DME) treated with intravitreal injections of anti-VEGF or dexamethasone.

A real-life, prospective, two-centre study was conducted over a 9-month period investigating diabetic patients presenting with unilateral DME treated with anti-VEGF or dexamethasone intravitreal injections, and CT was measured manually, using the enhanced depth imaging module of the spectral domain optical coherence tomography. Choroidal thickness (CT) was measured in the morning, in both the affected and healthy eye of each patient at two timepoints: when the macula was 'dry' (T0) and at the time of exudative recurrence (T1).

A total of 51 patients with unilateral DME were included. Mean CT in the affected eye was significantly thicker at the time of exudative recurrence (210.8 ± 44.1 μm at T0 versus 238.0 ± 49.0 μm at T1, p < 0.001). There was no significant variation in CT in the fellow eye (214.4 ± 52.3 µm at T0 versus 218.9 ± 53.4 µm at T1, p = 0.53). The type of intravitreal injection, the number of injections and the CT at T0 had no influence on the change in CT.

This study found that CT increased significantly in the affected eye at the time of recurrence of DME treated with anti-VEGF or dexamethasone injections. Choroidal thickness (CT) could constitute an interesting new indicator for monitoring patients with DME.