Association between optic disc pallor and lacunar stroke

Objective To test for associations between optic disc pallor and two clinical variables: ischaemic stroke subtype (cortical and lacunar) and cerebral small vessel disease (SVD) scores in a cohort of hospital patients admitted with mild stroke (Mild Stroke Study 1).Methods We used previously validated software, PallorMetrics, to quantify optic disc pallor in colour fundus photographs of patients diagnosed as having either cortical (n=92) or lacunar (n=92) stroke. We used logistic regression to assess the relationship between stroke type and disc pallor in several zones and ordinal logistic regression to assess the relationship between disc pallor and total SVD score. The left and right eyes were analysed separately.Results In the right eye, independent of age, sex, disc area, hypertension and diabetes, increased optic disc pallor was significantly associated with lacunar stroke in all zones (for global pallor: OR per SD increase=1.55, 95% CI 1.11 to 2.17, p=0.011) and total SVD score in the temporal superior (standardised β=0.36, SE=0.15, p=0.020) and nasal-inferior zones (standardised β=0.44, SE=0.15, p=0.004) in the right eye. Weaker trends were observed in the left eye; however, these did not reach statistical significance.Conclusion Optic disc pallor may be associated with SVD severity and lacunar stroke, which may reflect vascular damage to the optic nerve or its pathways. Our findings underscore the utility of colour fundus photography to learn more about SVD pathology.