Wide-field OCTA quantified peripheral nonperfusion areas predict the risk of subclinical neovascularization.

Purpose: To demonstrate the capabilities of single-shot widefield swept-source OCT angiography (SS-OCTA) in detecting subclinical retinal neovascularization (RNV), quantifying nonperfusion areas (NPAs), and exploring the relations between NPAs and subclinical RNV in eyes graded as nonproliferative diabetic retinopathy (NPDR).

Methods: Eyes clinically graded as moderate to severe NPDR underwent SS-OCTA imaging. Expert graders identified subclinical RNV, defined as vessels with a flow signal above the internal limiting membrane on OCTA that are not visible on dilated fundus examination. This identification was based on a combination of en face OCT, en face OCTA, and cross-sectional OCTA overlaid on OCT. NPA index was calculated as a percentage of automatically quantified NPA over the area in the posterior pole, the mid-periphery, and the total imaged area.

Results: Totally 37 eyes, including 21 had severe NPDR and 16 had moderate NPDR. Subclinical RNV was present in 14 eyes (37.8%). The eyes with RNV had significantly higher mid-peripheral and total NPA indices but not in the posterior region (mid-peripheral NPA: 31.97% ± 7.02% vs. 24.80% ± 6.60%, p = 0.041; total NPA: 27.96% ± 6.36% vs. 21.61% ± 5.65%, p = 0.046; all values are reported as mean ± standard deviation). The total NPA index showed the highest diagnostic accuracy for subclinical RNV detection (AUC: 0.761; 95% CI, 0.592-929, with a sensitivity of 64.3% and a specificity of 87% at a cutoff value of 28.84%).

Conclusion: Widefield SS-OCTA can detect subclinical RNV. The eyes with higher mid-peripheral NPA indices are more likely to have subclinical RNV, indicating that the NPA index may be a useful biomarker for identifying eyes at risk of RNV.