The study was prospective and cross-sectional. Only patients with age ≤55 years were included. We used a swept-source optical coherence tomography angiography device (Triton; Topcon, Tokyo, Japan) to obtain both quantitative and qualitative analysis of the retinal capillary plexuses (superficial capillary plexus; middle capillary plexus; and deep capillary plexus) and the choriocapillaris.
We included 17 patients with DM Type 1 (age 34.52 ± 11.05 years, 29 eyes), 17 patients with DM Type 2 (age 48.76 ± 3.26 years, 32 eyes), and 23 healthy control subjects (age 41.82 ± 8.97 years, 43 eyes). When compared with controls, vessel density in the central 1 mm was reduced in both DM Type 1 and DM Type 2 groups in the superficial capillary plexus (P = 0.05 and P = 0.02, respectively), and in DM Type 2 in the deep capillary plexus (P = 0.03). Foveal avascular zone was increased in the middle capillary plexus and deep capillary plexus of DM Type 2 group compared with controls (P = 0.03 and P = 0.02, respectively). Choriocapillary voids were more frequent in DM Type 1 and DM Type 2 compared with controls (P = 0.003 and P < 0.001, respectively).
Microvascular modifications are present in the three retinal capillary plexuses and the choriocapillaris in both DM Type 1 and DM Type 2 even in the absence of clinical signs of diabetic retinopathy.