BP instability may accelerate sight-threatening complications in adults with type 2 diabetes mellitus (T2DM). A study published in Eye evaluated the nonlinear associations between BP levels, BP variability, and DR development.The retrospective longitudinal cohort included 969 adults with T2DM and no DR at baseline, 

monitored between January 2018 and May 2023. BP was measured every 3–6 months, and DR was assessed annually using indirect ophthalmoscopy or fundus photography. Logistic regression examined relationships between BP parameters and incident DR.

Over a mean follow-up of 4.96 ± 0.96 years, 12.9% of participants developed DR. U-shaped or J-shaped patterns emerged, with lowest DR risk at systolic BP 130–135 mmHg, diastolic BP 75–80 mmHg, mean arterial pressure 95–100 mmHg, and pulse pressure 50–55 mmHg. Each 1-mmHg increase in the standard deviation (SD) of systolic, diastolic, mean arterial, and pulse pressures increased DR risk (odds ratios 1.108, 1.111, 1.085, and 1.133, respectively; all p < 0.001).

These findings highlight that both BP extremes and higher variability independently heighten DR risk in T2DM. Maintaining BP within stable, clinically optimal ranges may support DR prevention.