African Ancestry-Specific OCT Normative Database Alters Retinal Nerve Fiber Layer Classification in Primary...

Area of Science:

• Ophthalmology
• Medical Imaging
• Genetics

Background:

• The Cirrus HD-OCT normative database underrepresents structural differences in the retinal nerve fiber layer (RNFL) of African ancestry individuals.
• Previous research reclassified primary open-angle glaucoma (POAG) color codes using RNFL data from healthy African ancestry controls.

Purpose of the Study:

• To compare RNFL color-code classification between the standard Cirrus database and a reclassification model using an African ancestry-specific cohort for POAG cases.
• To assess the impact of an ancestry-conscious normative database on glaucoma diagnosis in African ancestry populations.

Main Methods:

• Utilized RNFL thickness data from 787 eyes of African ancestry participants in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study.
• Employed the Enhanced Glaucoma Staging System (GSS2) for eye staging.
• Reclassified RNFL thickness color codes based on a newly established African ancestry-specific cohort.

Main Results:

• The POAAGG reclassification model identified fewer abnormal (yellow and red) RNFL color codes (16.4% and 6.3%) compared to the Cirrus database (18.0% and 9.4%, P<0.001).
• Reclassification shifted a significant proportion of red codes to yellow/green (12.8%) and yellow codes to green (23.0%) (P<0.001).
• In stage 1 glaucoma, 19.0% of red codes and 23.1% of yellow codes shifted to greener classifications (P=0.04), with similar trends observed in quadrant-specific analyses.

Conclusions:

• Discrepancies in POAG color-code classification highlight the need for ancestry-conscious normative databases.
• Implementing an ancestry-conscious approach may help reduce the overdiagnosis of POAG in African ancestry individuals.
• The study demonstrated a lower occurrence of POAG in African ancestry patients when considering their ancestry-specific data compared to the Cirrus HD-OCT classification.