Tâche noire de la sclérotique
Forensic Pathology: Post-Mortem Eye Changes
1. Definition
Tache noire (French for “black spot”) is a post-mortem change observed on the sclera (white of the eye). It manifests as a brownish-black, triangular, or oval patch that develops when the eyelids are left partially open after death.
2. Mechanism
This phenomenon occurs due to the **drying and exposure of the sclera** to the air when the eyes remain open post-mortem. The underlying choroidal pigment becomes visible through the desiccated, thin, and transparent scleral tissue, creating the appearance of a dark, dry spot.
3. Forensic Significance
| Feature | Detail |
|---|---|
| Location | Typically, on the lateral and medial aspects of the sclera. |
| Diagnostic Utility | Acts as a visual marker for the Post-Mortem Interval (PMI). |
| Visibility | Becomes prominent within a few hours of death. |
4. Forensic High-Yield Pearls
- Caution: Tache noire can easily be mistaken for ante-mortem bruising or hemorrhage. Careful inspection reveals the dry, parchment-like texture of the sclera, which distinguishes it from vascular injury.
- PMI Estimation: While not precise, the presence and extent of Tache noire can help refine the estimation of the time since death, especially when correlated with other findings like corneal opacity and skin desiccation.