For two consecutive annual physicals, a 33-year-old female aircrew member with China's air force was told the glinting specks in her left eye were synchysis scintillans, a rare degeneration in which cholesterol crystals float loose inside a liquefied vitreous. Both diagnoses came from a slit lamp and nothing else, with no ultrasound and no optical coherence tomography.
At her third exam, someone moved her eye and watched what the specks did. They shifted slightly, then snapped back to where they started. That single dynamic observation, backed by ultrasound, overturned the diagnosis. She had asteroid hyalosis, a condition her ophthalmologists had effectively ruled out on the basis of her birthday.
