Yellow RNFL Defects on Zeiss OCT Reporting
Describe yellow-coded areas as "borderline RNFL thinning" with specific clock-hour location and whether diffuse or localized pattern is present.
Understanding the Color Coding
On Zeiss OCT RNFL deviation maps, yellow indicates borderline thinning (typically between 1st-5th percentile compared to normative database), positioned between normal (green) and abnormal (red) ranges. This represents early or equivocal RNFL loss that requires clinical correlation.
Recommended Reporting Structure
When documenting yellow defects, include:
- Location: Specify clock-hour position(s) or quadrant (e.g., "inferotemporal at 7-8 o'clock")
- Pattern classification:
- Extent: Note if isolated or part of broader thinning pattern
Clinical Context Matters
Critical caveat: Yellow defects alone do not confirm glaucoma 3. The guidelines emphasize that RNFL abnormalities must be interpreted alongside:
- Optic disc appearance (rim notching, asymmetry, hemorrhages)
- Visual field testing results
- Baseline IOP measurements
- Absence of other explanations (optic neuritis, ischemic neuropathy, anatomical variants) 4
Common Pitfalls
Anatomical variation causes false-positive alerts in over 60% of healthy eyes 5. Yellow defects may reflect:
- Wider or narrower temporal nerve fiber ridge angles
- Macular size variations
- Normal papillomacular bundle thinning
Always correlate with fundus examination and photography. Research shows that even red-coded defects can be missed without proper clinical context 6, 7.
Practical Example
"Borderline RNFL thinning (yellow-coded) in inferotemporal quadrant at 7-8 o'clock, localized pattern. Correlate with optic disc examination and visual field testing to determine clinical significance."