Association between vision impairment and depression: a 9-year, longitudinal, nationwide, population-based cohort study in South Korea

Vision impairment (VI) increases the risk of various comorbidities, including depression. However, the relationship between depression and VI is unclear, and existing findings are inconsistent. We therefore investigated the risk of depression in adults before and after their registration as visually impaired.In this longitudinal, nationwide, retrospective cohort study, 131 434 patients (aged ≥18 years) with newly registered VI during 2005-2013 were evaluated using the Korean National Health Insurance Service database. Using 1:1 propensity score matching, randomly selected patients (control group) were compared with patients with VI (patient group) according to age, sex, residential area and household income. Each patient was tracked from 3 years before and 5 years after registration. The risk of depression before and after VI registration was evaluated using a conditional logistic regression model.The risk of depression gradually increased from 3 years before registration (OR, 1.186; 95% CI 1.089 to 1.290), then peaked at the time of registration (OR, 1.925; 95% CI 1.788 to 2.073), and then gradually decreased until 5 years after registration (OR, 1.128; 95% CI 1.046 to 1.216). Male patients, those with severe VI and those aged 18-29 years had a higher risk of depression.Patients with VI had an increased risk of depression from 3 years before to 5 years after registration. Significant risk factors included severity, male sex and younger age. Thus, public mental health services are necessary to provide appropriate support and interventions to people before and after registration as visually impaired.