{
  "abstract": "Background/aims To characterise the distribution of retinal non-perfusion and its relationship with neovascularisation elsewhere (NVE) and visual acuity (VA) in referable diabetic retinopathy (DR) using ultra-widefield fluorescein angiography (UWFA).Methods Eyes with treatment-naïve moderately severe non-proliferative DR (NPDR) to proliferative diabetic retinopathy (PDR) (Diabetic Retinopathy Severity Scale (DRSS) level 43–60) with available UWFA were included in this study. Total and zonal non-perfusion and NVE area were manually delineated across concentric zones (central 1–10 mm, extended posterior >10–20 mm and mid-peripheral >20–30 mm diameter). The Non-Perfusion Index (NPI) was calculated as the ratio of non-perfused area to total area per zone. Associations between NPI, NVE, DR severity and best-recorded VA (BRVA) were assessed.Results A total of 133 eyes (60.9% NPDR, 39.1% PDR) were analysed. The highest NPI occurred in the mid-periphery (20–30 mm) and posterior pole (15–20 mm) zones, with nasal preponderance. NVE was most frequently observed in the posterior pole (66%) and nasal quadrants. Central and mid-peripheral NPI correlated with NVE area in corresponding zones, showing quadrant-specific associations. Receiver operating characteristic analysis identified a total NPI threshold of 0.23 to differentiate PDR from NPDR (area under the curve=0.798), with the lowest threshold in the superior quadrant. Neither NPI nor NVE area correlated with BRVA.Conclusion NVE represents a localised response to adjacent ischaemia predominantly affecting the nasal and extended posterior retina. NPI threshold of 0.23 distinguishes proliferative from non-proliferative stages, with the superior quadrant showing greater susceptibility to NVE at lower ischaemic levels. No significant correlation found between NPI, NVE area and visual acuity.",
  "authors": [
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK",
        "Tanta University Faculty of Medicine, Tanta, Egypt"
      ],
      "name": "Hagar Khalid"
    },
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK",
        "Hampshire Hospitals NHS Foundation Trust, Winchester, UK"
      ],
      "name": "Wei-Shan Tsai"
    },
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK"
      ],
      "name": "Francesca Lamanna"
    },
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK"
      ],
      "name": "Eleonora Riotto"
    },
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK"
      ],
      "name": "Sarega Gurudas"
    },
    {
      "affiliations": [
        "Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany"
      ],
      "name": "Louise Roch"
    },
    {
      "affiliations": [
        "Moorfields Eye Hospital NHS Foundation Trust, London, UK"
      ],
      "name": "Sobha Sivaprasad"
    }
  ],
  "title": "Quantification of retinal non-perfusion in eyes with diabetic retinopathy to study the association with retinal neovascularisation: INSPIRED study report 3",
  "uid": "572be317-a70e-51c8-a416-82f5f1a62a0c"
}