A severity scale for diabetic macular edema developed from ETDRS data

Area of Science:

• Ophthalmology
• Retinal Diseases
• Diabetic Retinopathy

Background:

• Diabetic macular edema (DME) is a leading cause of vision loss in diabetic patients.
• Accurate assessment of DME severity and its impact on visual acuity (VA) is crucial for patient management.

Purpose of the Study:

• To develop and validate a severity scale for diabetic macular edema (DME).
• To evaluate the relationship between DME severity, duration, and visual acuity (VA).

Main Methods:

• Utilized data from 7422 eyes in the Early Treatment Diabetic Retinopathy Study (ETDRS).
• Developed a nine-step DME severity scale based on retinal thickening location, area, and degree, merging similar baseline VA categories.
• Analyzed relationships between the scale, baseline VA, and other clinical characteristics.

Main Results:

• The nine-step DME severity scale explained 38.0% of the variance in baseline visual acuity (VA).
• VA decreased significantly across scale levels, from 86.8 letters at level 1A to 59.8 letters at level 5B.
• Visual acuity loss accelerated with longer duration at higher DME severity levels, reaching 17 letters per year at level 5B.

Conclusions:

• The developed nine-step scale effectively quantifies DME severity.
• The scale facilitates documentation of the impact of DME severity and duration on visual acuity.
• This tool aids in understanding the progression of vision loss in DME patients.