Retinal Perfusion and Injury in Sepsis and after Major Surgery

Objective To assess retinal perfusion in sepsis, compared with uncomplicated post-operative care and healthy controls, and to assess the effects of reduced perfusion on retinal structure and visual function. Design We conducted a prospective observational cohort study between March 2018 and December 2022, with follow-up measures collected 3-6 months after discharge from hospital Subjects The study recruited 24 patients with sepsis assessed in the intensive care unit (ICU) and 3-6 months later, 45 ICU control patients assessed during elective ICU admission after upper gastrointestinal cancer surgery, pre-operatively, and 3-6 months later, and 15 healthy controls. Testing Assessments included retinal layer thickness using optical coherence tomography (OCT), retinal perfusion using OCT angiography (OCTA), and visual function using Humphrey visual field (HVF) analysis. Organ dysfunction was assessed by Sequential Organ Failure Assessment (SOFA) scoring. Main Outcome Measures The main outcome measures included: superficial vascular plexus (SVP) retinal perfusion; OCT retinal ganglion cell layer (GCL) thickness; and mean deviation (MD) on Swedish interactive thresholding algorithm 10-2 HVF testing. Results SVP retinal perfusion was 37% lower in patients with sepsis compared with ICU control patients (p<0ꞏ001), and 61% lower than in healthy controls, and returned to normal by final follow-up. Retinal perfusion moderately correlated with the SOFA score (Pearson's r=0.57, p<0.001) and weakly correlated with C-reactive protein (r=0.337, p=0.01) and mean arterial pressure (r=0.354, p=0.006). In both patients with sepsis and ICU controls, retinal perfusion in ICU predicted both subsequent GCL thickening, with every 1 unit decrease in SVP sum predicting a 1.88μm increase in GCL thickness at follow-up (p=0.003), and worsening visual field MD, with a every 1 unit decrease in SVP sum predicting a 0.078dB lower MD (p=0.023). Conclusions Retinal perfusion was impaired in patients with sepsis compared with both healthy controls and patients who had undergone major surgery. It was moderately associated with other measures of organ dysfunction assessed by SOFA. Reduced retinal perfusion in both patients with sepsis and patients after major surgery strongly associated with subsequent GCL thickening, and less strongly with increased visual field mean deviation, suggesting reduced retinal perfusion is associated with retinal damage, with consequent visual dysfunction.