Involvements of choroidal vascular structures with local treatments in patients with diabetic macular edema

To examine changes of the choroidal morphology in patients with diabetic macular edema (DME) before and after local treatments.

This study was on 20 eyes with DME, observed for more than 24 months. All patients underwent laser photocoagulation (Laser), sub-tenon triamcinolone acetonide injection (TA), or intravitreal aflibercept injection (IVA). Central macular and choroidal thicknesses (CMT/CCT), and choroidal vascular structures consisting of the total choroidal area (TCA), luminal area (LA), and stromal area (SA) were measured by a binarization method. The ratios of LA in TCA were eventually determined as the L/C ratio in each case.

The L/C ratio significantly decreased for 24 months in patients with DME (p = 0.01), whereas no significant differences were noted in other parameters including TCA, LA, SA, or CCT. Among patients treated with Laser ± TA ± IVA, a significant correlation was found between a high L/C ratio at pretreatment and a lower cumulative number of injections (1-2 times/24 months) (p = 0.04). The L/C ratio in pretreatment showed a significantly inverse correlation with CMT (-0.60, p = 0.02) and subsequent BCVA (logMAR) (-0.59, p = 0.03).

This study highlighted that the L/C ratio in pretreatment might predict a change of the visual acuity in DME.