Targeted retinopathy screening may be possible in type 1 diabetes

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  • Depending on a patient’s current retinopathy state and HbA1c, intervals between retinopathy screenings can range from 3 mo to 4 y, vs annual exams currently recommended.

Why this matters

  •  Diabetes is number 1 blindness cause, but exams are costly.

Study design

  • Data from 1375 patients in Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study.
  • 7-field fundus photographs taken every 6 mo in DCCT, and every 4 y during EDIC.
  • Diabetic retinopathy states were classified as 1 (no retinopathy), 2 (mild nonproliferative), 3 (moderate nonproliferative), 4 (severe nonproliferative), and 5 (proliferative diabetic retinopathy [PDR], clinically significant macular edema [CSME], or prior treatment).
  • Aim was to limit progression from states 1-4 to 5 to <5% between exams.  
  • Funding:NIH.

Key results

  • Probability of progression to PDR/CSME was <5% at 4 y, 3 y, 6 mo, and 3 mo for retinopathy states 1-4, respectively.
  • For every 1% rise in HbA1c, HRs for progression to PDR/CSME ranged from 1.15 to 1.60 for states 1-4, respectively.
  • During 20 y, model lowered eye exam frequency by 58%, leading to $1 billion in savings.


  • Reliance on 7-field fundus photography.
  • Model may not apply to other populations.