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

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

Methods: 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.

Results: The L/C ratio significantly decreased for 24 months in patients with DME ( = 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) ( = 0.04). The L/C ratio in pretreatment showed a significantly inverse correlation with CMT (-0.60,  = 0.02) and subsequent BCVA (logMAR) (-0.59,  = 0.03).

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