I believe there was once a theory that the image of a murderer could be burned in (captured) on the eyes of the murder victim. This proved to be incorrect.
But perhaps we’re getting closer. Image if Seth Rich had these. It would have meant even more evidence that the FBI would have had to destroy.
Ok so then they just take the contacts and destroy them, and we have no evidence.
IMagine a Deep State FBI agent asking, “Did...you just blink me?” All they have to do, is remove your contacts...if not your eyes.