Incidence and treatment patterns of acute retinal necrosis: a nationwide population-based cohort study

To quantify nationwide incidence and contemporary treatment patterns of acute retinal necrosis (ARN).

Retrospective cohort using Japan's National Database of Health Insurance Claims and Specific Health Checkups, which covers >95% of claims. New-onset ARN (2016-2022) was identified by ARN diagnostic codes plus antiviral therapy. Annual, age-specific and sex-specific incidence rates used governmental denominators; age-standardised rates used the WHO world standard. Surgical management (vitreoretinal surgery, silicone oil (SO)/perfluorocarbon (PFC) use, glaucoma surgery) was assessed up to 2 years after diagnosis.

Among 586 incident cases (313 men, 273 women), crude incidence was 0.066 (95% CI 0.061 to 0.072) per 100 000 person-years; the age-standardised rate was 0.040 per 100 000 person-years. Incidence rose with age, peaking at 70-74 years, and was consistently higher in men than in women. Vitreoretinal surgery occurred in 42.4% by 30 days and 59.4% by 365 days after diagnosis; 25.1% underwent ≥2 procedures within 1 year. SO or PFC was used in 40.8% by 1 year. Glaucoma surgery was uncommon (<2% by 2 years).

In the largest population-based study of ARN to date, nationwide incidence in Japan closely matched prior UK estimates, suggesting cross-system consistency in ARN epidemiology. Management was characterised by early, intensive surgery with frequent tamponade use and substantial reoperation, informing clinical triage and resource planning for this rare, vision-threatening condition.