**What the ANW is**
The ANW (Autonomic Nerve Wreath), also called the collarette, is a textured ring visible in the iris approximately one-third of the way between the pupil and the iris rim. It marks the transition between the inner and outer iris zones and reflects autonomic nervous system tone.
**ANW Ratio**
The ratio measures the ANW ring diameter relative to the iris diameter.
| ANW Ratio | Status | Autonomic interpretation |
|———–|——–|————————-|
| < 25% | **Spastic** | ANW ring contracted inward — sympathetic dominance, hypertonicity |
| 25–35% | **Normal** | Balanced autonomic tone |
| > 35% | **Atonic** | ANW ring expanded outward — parasympathetic dominance, hypotonicity |
**ANW Asymmetry**
The asymmetry between OD and OS ANW ratios is also measured. An asymmetry of **0–5%** is normal. A larger asymmetry, particularly where one eye is Spastic and the other is Atonic, is flagged as a **Functional Frustration** pattern.
**ANW Shifts**
Local sectors of the ANW ring that deviate inward or outward from their expected position by more than **8%** are reported as ANW Shift findings (badge: **ANW**). Like FLAT/PROT findings, each shift is mapped to a clock zone and assigned its historical organ association.
**Bilateral comparison**
After both eyes are analysed, the bilateral ANW summary compares OD and OS ratios side-by-side, calculates the asymmetry, and flags the functional frustration pattern if present.
