Regardless of capture mode, the following practices produce the best analysis results:
**Lighting**
– Use diffuse, even illumination — the built-in iriscope LED ring is ideal.
– Avoid harsh shadows across the iris.
– Avoid reflections from overhead lights on the cornea; slight repositioning eliminates most reflections.
**Distance & framing**
– The iris should fill at least 50% of the frame width.
– Keep the iris centred; a pupil near the edge of the frame reduces decentration accuracy.
– For the Dino-Lite, the optimal focal distance is approximately 2–3 cm from the eye.
**Stability**
– Rest the device or brace your hand to eliminate motion blur.
– Ask the patient to fixate on a distant point to minimise involuntary eye movement.
– Capture during natural blinking pauses — the image quality gate automatically rejects frames taken during a blink.
**Grade guide**
After analysis, each eye receives a quality grade:
| Grade | Meaning |
|——-|———|
| **A** | High confidence — all metrics within optimal range |
| **B** | Good confidence — minor limitations, results reliable |
| **C** | Reduced confidence — consider recapture if possible |
| **D** | Low confidence — recapture recommended before clinical use |
