Colombian Ocular Inflammatory Diseases Epidemiology Study (COIDES): Optic Neuritis Incidence Between 2015-2020.

Purpose: To estimate the incidence of Optic Neuritis (ON) in Colombia using data from the national health registry between January 1, 2015, and December 31, 2020.
Methods: A population-based study was conducted using the Integrated Social Protection Information System from the Colombian Ministry of Health and the International Classification of Diseases-10 code for ON to estimate the incidence of ON from 2015 to 2020. We also evaluated the impact of the COVID-19 lockdown on the epidemiology of the disease in 2020. Finally, a standardized morbidity rate map was created to assess a country's ON geographic distribution.
Results: From 2015 to 2019, 2,463 new cases of ON were reported. The overall 5-year incidence rate was 1.56 cases per 100,000 inhabitants per year, 66% of the patients were females. The peak of presentation in males was the quinquennium of 50-54 years, and in females, it was 45-49 years. In 2020, coinciding with the COVID-19 pandemic, there was a reduction in the incidence of ON by approximately 0.15 cases per 100,000 inhabitants. The regions with a high number of cases and an increasing risk of new cases were Bogotá, Antioquia, and Valle del Cauca.
Conclusions: The incidence of ON in Colombia is lower compared to countries in the northern hemisphere, with women under 50 years being predominantly affected. The onset of the COVID-19 pandemic corresponded with a reduction in identifying new ON cases. This underscores governments' need to implement effective diagnostic strategies in the future.