It remains unclear whether the distribution of lesions in the retinal periphery affects the correlation between diabetic retinopathy (DR) severity and macular vessel density. A cross-sectional, observational study sought to determine the correlation of DR lesion distribution with optical coherence tomography angiography (OCTA) metrics and disease severity.
The study took place at a tertiary care center for diabetic eye disease. A total of 225 patients (352 eyes) with type 1 or 2 diabetes underwent imaging between February 15, 2016, and December 31, 2019. The cohort was 55.6% male, and the mean age was 52.1 years. The main outcomes were OCTA vessel density in the superficial capillary plexus, intermediate capillary plexus, and deep capillary plexus and choriocapillaris flow density; DR severity and the predominantly peripheral lesions (PPLs) were evaluated using ultra-widefield color imaging.
Among the 352 eyes, 183 (52%) had mild non-proliferative DR (NPDR), 71 (20.2%) had moderate NPDR, and 98 (27.8%) had severe NPDR or proliferative DR (PDR).
Among the 209 eyes (59.4%) with no PPL, decreases were observed with increasing DR severity in the mean (standard deviation [SD]) vessel density in the superficial capillary plexus (mild NPDR, 38.1% [4.7%]; moderate NPDR, 36.4% [4.6%]; severe NPDR or PDR, 34.1% [4.1%]; P<0.001), the deep capillary plexus (mild NPDR, 45.8% [3.0%]; moderate NPDR, 45.8% [2.2%]; severe NPDR or PDR, 44.5% [1.9%]; P=0.002), and choriocapillaris flow density (mild NPDR, 69.7% [6.2%]; moderate NPDR, 67.6% [5.6%]; severe NPDR or PDR, 67.1% [5.6%]; P=0.01). When adjusting for age, signal strength index, spherical equivalent, diabetes duration and type, and correlation between eyes of the same patient, the outcomes still persisted.
Among the 143 eyes (40.6%) with PPL, increasing DR severity was not impacted by mean (SD) vessel density in the superficial capillary plexus (mild NPDR, 34.1% [4.1%]; moderate NPDR, 35.2% [4.1%]; severe NPDR or PDR, 36.0% [4.3%]; P=0.42), deep capillary plexus (mild NPDR, 44.5% [1.7%]; moderate NPDR, 45.4% [1.4%]; severe NPDR or PDR, 44.9% [1.5%]; P=0.81), or choriocapillaris flow density (mild NPDR, 67.1% [5.6%]; moderate NPDR, 69.3% [4.6%]; severe NPDR or PDR, 68.3% [5.6%]; P=0.49).
“If DR onset and worsening are associated with the location of retinal non-perfusion, assessment of global retinal nonperfusion using widefield angiography may improve the ability to evaluate DR severity and risk of DR worsening over time,” the study authors concluded.