Constitutional type selection is performed on the **”Both Eyes Captured”** screen, which appears after both left and right eye photos have been taken. At this point the practitioner has both eye images visible side by side — the appropriate moment for constitutional assessment, since Deck’s system requires evaluation of both irides together.
**To select a type (Windows desktop only):**
1. Complete the right eye capture (Step 1 of 2).
2. Complete the left eye capture. The screen title changes to **”Both Eyes Captured”** when both images are present.
3. Scroll below the eye image pair. An amber-bordered panel labelled **”Constitutional Type (Optional)”** is visible.
4. Click the dropdown to open it. Types are organized by group with non-selectable group dividers.
5. Select the appropriate type. The type name is confirmed below the dropdown.
6. Leave the dropdown at **”None (not assessed)”** to omit the constitutional section entirely from the analysis and PDF.
7. Tap **Analyze Both Eyes** to proceed.
> **Session persistence:** The selected type is held in memory for the current session. If you navigate back to the Both-Eyes-Captured screen, the previously selected type is restored. The selection is cleared when a new scan session begins from the home screen.
**Assessment approach:** Constitutional typing requires experience and ideally evaluation of the iris under magnification (slit lamp or iriscope). The practitioner should consider:
– **Iris base color** — blue-grey → Lymphatic group; dark brown → Haematogenic; light brown/mixed → Biliary/Mixed
– **Fiber density and texture** — tight/silk-like vs. loose/wavy vs. coarsely woven with lacunae
– **Tophi and plaques** — presence, definition, and color of connective-tissue deposits
– **Pigmentation pattern** — central heterochromia, scurf rim, liver-zone pigments, dispersed spots
– **Special structures** — cramp rings, heart-zone defect markings, arcus senilis/lipaemic ring
When the constitutional group is clear but the exact subtype is uncertain, selecting the base type (e.g., *Pure Lymphatic*, *Classic Biliary*, *Haematogenic I*) is preferable to guessing a complex subtype.
