---
title: 3.3 Zone Findings — Flattenings (FLAT) and Protrusions (PROT)
description: "****What they are**** The pupil margin is assessed for local deviations from a perfect circle. Two types of deviation are detected: | Badge | Shape | Historical interpretation | |-------|-------|--------------------------| | ****FLAT**** | Pupil margin curves **inward** at a zone…"
url: "https://cnri.edu/docs/3-3-zone-findings-flattenings-flat-and-protrusions-prot/"
updated: "2026-03-24"
category: Reading the Analysis Results
---

# 3.3 Zone Findings — Flattenings (FLAT) and Protrusions (PROT)

****What they are****

The pupil margin is assessed for local deviations from a perfect circle. Two types of deviation are detected:

| Badge | Shape | Historical interpretation |

|-------|-------|--------------------------|

| ****FLAT**** | Pupil margin curves **inward** at a zone | Reduced autonomic tone in that zone's reflex area |

| ****PROT**** | Pupil margin **bulges outward** at a zone | Increased sympathetic activity in that zone |

****Severity scale****

Each finding is graded by the percentage deviation from the expected circular margin:

| Severity | Deviation | Meaning |

|----------|-----------|---------|

| Within limits | 1.5–3.0% | Minor variation, not clinically flagged |

| Mild | 3.0–6.0% | Notable deviation, noted for observation |

| Moderate | 6.0–10.0% | Significant deviation, worth follow-up |

| Significant | > 10.0% | Strong deviation, primary clinical focus |

Deviations below 1.5% are not reported. Each zone card shows the severity percentage, the zone name, the eye (OD/OS), and the historical organ association for that zone.