---
title: 3.5 Decentration (Pupil Position)
description: "****What it is**** Decentration measures how far the pupil center is offset from the geometrical center of the iris, expressed as a percentage of the iris radius. | Decentration | Classification | |-------------|----------------| | < 5% | ****Normal**** — pupil…"
url: "https://cnri.edu/docs/3-5-decentration-pupil-position/"
updated: "2026-03-24"
category: Reading the Analysis Results
---

# 3.5 Decentration (Pupil Position)

****What it is****

Decentration measures how far the pupil center is offset from the geometrical center of the iris, expressed as a percentage of the iris radius.

| Decentration | Classification |

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

| < 5% | ****Normal**** — pupil centered within physiological limits |

| ≥ 5% | ****Notable**** — decentration flagged with directional pattern |

****Directional patterns****

When decentration is notable, the direction is reported as a named pattern:

| Direction | Pattern name | Zone implication |

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

| Toward nose | Nasal | OD: pulmonary reflexes · OS: cardiac reflexes |

| Away from nose | Temporal | Renal, reproductive zones |

| Upward | Frontal | Cerebral, cognitive zones |

| Downward | Basal | OD: intracranial pressure reflexes · OS: cerebral patterns |

| Upper-inward | Upper-nasal | OD: hepatobiliary · OS: splenic, diaphragmatic |

| Upper-outward | Upper-temporal | Renal, reproductive zones |

The decentration angle is also reported in degrees (0–360°) from the horizontal, providing precise directional information for charting.