Evaluation of Retinal Edema in Nonproliferative Diabetic Retinopathy Using Widefield Swept-Source OCT

This study evaluates retinal volume in the macula and peripheral retina in patients with nonproliferative diabetic retinopathy (NPDR), with and without diabetic macular edema (DME), using widefield swept-source OCT (SS-OCT).

Retrospective observational study.

A total of 98 eyes were included: 30 from patients with NPDR without DME (DME-), 38 from patients with NPDR with DME (DME+), and 30 from age- and sex-matched healthy controls.

OCT examinations used SS-OCT (Xephilio OCT-S1; Canon) to capture 23 × 20 mm (1024 × 128 A-scans) cube images. Retinal volume was calculated for each sector in a 9-sector grid defined by concentric circles (1 mm, 6 mm, and 20 mm in diameter) centered on the fovea and divided into four quadrants: superior, inferior, nasal, and temporal. The macular region was defined within a 6-mm diameter, whereas the peripheral retina spanned 6 mm to 20 mm.

Macular and peripheral retinal volumes measured from SS-OCT images in each group.

A total of 98 eyes were analyzed (control: 30; DME-: 30; DME+: 38). Macular retinal volume was 8.46 ± 0.49 mm³ in the control group, 8.79 ± 0.55 mm³ in the DME-group, and significantly higher at 10.53 ± 1.81 mm³ in the DME + group (P < 0.0001). Peripheral retinal volume was 64.5 ± 3.1 mm³ in the control group, 62.2 ± 3.7 mm³ in the DME-group, and significantly higher at 68.7 ± 10.4 mm³ in the DME + group (P < 0.001). In DME+, severe NPDR showed greater volumes (macula: 11.2 ± 1.9 mm³; periphery: 71.9 ± 13.0 mm³) than mild-to-moderate NPDR (macula: 9.67 ± 1.14 mm³; periphery: 65.1 ± 4.6 mm³; P < 0.01 and P < 0.05, respectively).

Our findings indicate that retinal volume increases in both macular and peripheral regions in DME, particularly as NPDR severity progresses.

The author has no/the authors have no proprietary or commercial interest in any materials discussed in this article.